Method for transmitting and receiving uplink data in wireless communication system and device for same

ABSTRACT

The present description provides a method for transmitting and receiving uplink (UL) data in a wireless communication system. A method, which is carried out by means of a terminal, comprises the steps of: receiving a first uplink grant from a base station; transmitting, on the basis of the first uplink grant, first uplink data to the base station; receiving an HARQ response to the first uplink data from the base station; transmitting second uplink data to the base station by means of retransmission resources allocated for the retransmission of the first uplink data; and transmitting, to the base station, control information which indicates whether the second uplink data is retransmission data of the first uplink data or new data generated by means of a particular event.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2015/013067, filed on Dec. 2, 2015,which claims the benefit of U.S. Provisional Application No. 62/187,827,filed on Jul. 2, 2015, the contents of which are all hereby incorporatedby reference herein in its entirety.

TECHNICAL FIELD

The present invention relates to wireless communication systems, andmore particularly, to a method for transmitting and receiving uplinkdata and an apparatus for supporting the same.

BACKGROUND ART

Mobile communication systems have been developed to provide voiceservices, while guaranteeing user activity. Service coverage of mobilecommunication systems, however, has extended even to data services, aswell as voice services, and currently, an explosive increase in traffichas resulted in shortage of resource and user demand for a high speedservices, requiring advanced mobile communication systems.

The requirements of the next-generation mobile communication system mayinclude supporting huge data traffic, a remarkable increase in thetransfer rate of each user, the accommodation of a significantlyincreased number of connection devices, very low end-to-end latency, andhigh energy efficiency. To this end, various techniques, such as smallcell enhancement, dual connectivity, massive Multiple Input MultipleOutput (MIMO), in-band full duplex, non-orthogonal multiple access(NOMA), supporting super-wide band, and device networking, have beenresearched.

DISCLOSURE Technical Problem

Previously, a user equipment may transmit data faster by occupyingresource by data of which priority is high according to uplink dataprioritization in the user equipment by using the resource allocated tothe user equipment itself.

However, in the case that a user equipment transmits data which isdifferent from that of an initial transmission by using HARQretransmission resource, a problem may occur that HARQ process is failedto operate properly as described above.

The retransmission resource of a user equipment is also a resource thata base station allocates to the user equipment. However, owing to thereason described above, even in the case that data of high priorityoccurs to the user equipment, an abruptly generated data may betransmitted by allocating with a new resource only after waiting for theretransmission of the previous data being completed.

As such, in the case that HARQ retransmission is performing on the timewhen urgent data is generated, long time delay may occur for a userequipment to perform a resource request for urgent data transmission.

In the worst case, in the case that HARQ retransmission occurs as muchas the maximum retransmission count and all (8 for LTE) HARQ processesare performing, a user equipment is able to be newly allocated with aresource for urgent data after maximum 32 ms.

Accordingly, the present disclosure proposes, in the case that it isrequired to transmit urgent data when an urgent event occurs, a methodfor transmitting urgent data by using the resource allocated to the userequipment itself.

Particularly, an object of the present disclosure is to provide a methodfor defining and transmitting new data indication (NDI) informationindicating whether the uplink data transmitted and received throughretransmission data is retransmission data or new data.

In addition, object of the present disclosure is to provide a method fortransmitting the NDI information through a PUSCH resource.

The technical objects to attain in the present disclosure are notlimited to the above-described technical objects and other technicalobjects which are not described herein will become apparent to thoseskilled in the art from the following description.

Technical Solution

In the present disclosure, a method for transmitting and receivinguplink (UL) data performed by a user equipment (UE) in a wirelesscommunication system includes receiving a first UL grant from a basestation (BS); transmitting a first UL data to the BS based on the firstUL grant; receiving a HARQ response of the first UL data from the BS;transmitting a second UL data to the BS based on a retransmissionresource allocated for retransmitting the first UL data; andtransmitting control information indicating whether the second UL datais a retransmission data of the first UL data or a new data generateddue to a specific event to the BS.

In addition, in the present disclosure, the control information istransmitted to the BS in a PUSCH resource.

In addition, in the present disclosure, the control information includesthe second UL data and a MAC packet data unit (PDU), and the MAC PDUfurther includes PHY header including the control information.

In addition, in the present disclosure, the PHY header further includesPHY header Indicator (PHI) field indicating whether the PHY header isincluded in the MAC PDU.

In addition, in the present disclosure, the PHY header is added in frontof MAC header.

In addition, the present disclosure further includes receiving a secondUL grant from the BS; and transmitting the second UL data to the BSbased on the received second UL grant, when the second UL data is theretransmission data of the first UL data.

In addition, in the present disclosure, the second UL grant is receivedfrom the BS together with the HARQ response.

In addition, in the present disclosure, the control informationindicates a type of CRC, the control information uses a first CRC typewhen the second UL data is the retransmission data of the first UL data,and the control uses a second CRC type when the second UL data is thenew data.

In addition, in the present disclosure, the type of CRC is determineddepending on whether a transport block (TB) of the retransmission dataor the new data is segmented.

In addition, in the present disclosure, the second UL data or thecontrol information is multiplexed.

In addition, in the present disclosure, the control information ismapped to a specific resource element (RE) of the retransmissionresource.

In addition, in the present disclosure, a transport resource of thesecond UL data and a transport resource of the control information arenot overlapped.

In addition, in the present disclosure, the control information ismapped to at least one symbol of a lowest subcarrier index of theretransmission resource or mapped to at least one symbol of a centersubcarrier index of the retransmission resource.

In addition, the present disclosure further includes receiving adownlink (DL) data to the BS; and transmitting a HARQ response of thereceived DL data to the BS, and the control information is transmittedwith being multiplexed with the HARQ response of the received DL data.

In addition, in the present disclosure, the control information and theHARQ response of the received DL data are distinguished by an orthogonalsequence.

In addition, in the present disclosure, the HARQ response of the firstUL data is HARQ NACK.

In addition, in the present disclosure, a method for transmitting andreceiving uplink (UL) data performed by a base station (BS) in awireless communication system includes transmitting a first UL grantfrom a user equipment (UE); receiving a first UL data from the UE;transmitting a HARQ response of the first UL data to the UE; receiving asecond UL data through a retransmission resource allocated to the UE forretransmitting the first UL data from the UE; and receiving controlinformation indicating whether the second UL data is a retransmissiondata of the first UL data or a new data generated due to a specificevent from the UE.

In addition, the present disclosure further includes determining toperform HARQ combining between the first UL data and the second UL databased on the received control information.

In addition, in the present disclosure, when the second UL dataindicates retransmission data of the first UL data, the first UL dataand the second UL data are HARQ combined, and when the second UL dataindicates the new data, the first UL data stored in a HARQ buffer isdiscarded or separately stored.

In addition, the present disclosure further includes transmitting HARQNACK indicating a reception failure of the first UL data to the UE; andreceiving the retransmission data of the first UL data from the UE whenthe second UL data is the new data.

In addition, the present disclosure further includes transmitting HARQNACK indicating a reception failure of the first UL data to the UE; andreceiving the retransmission data of the second UL data from the UE whenthe second UL data is the new data.

In addition, the present disclosure further includes transmitting asecond UL grant for newly allocating a retransmission resource of thefirst UL data to the UE; and receiving the retransmission data of thefirst UL data from the UE based on the second UL grant.

In addition, the present disclosure further includes transmittingindication information for indicating that a HARQ process ID of thefirst UL data is changed to the UE.

In addition, in the present disclosure, the indication information isincluded in the second UL grant.

In addition, in the present disclosure, a user equipment (UE) fortransmitting and receiving uplink (UL) data in a wireless communicationsystem includes a radio frequency (RF) unit for transmitting andreceiving a radio signal; and a processor functionally connected to theRF unit, and the processor is configured to perform: receiving a firstUL grant from a base station (BS); transmitting a first UL data to theBS based on the first UL grant; receiving a HARQ response of the firstUL data from the BS; transmitting a second UL data to the BS based on aretransmission resource allocated for retransmitting the first UL data;and transmitting control information indicating whether the second ULdata is retransmission data of the first UL data or new data generateddue to a specific event to the BS.

Technical Effects

According to the present disclosure, there is an effect of decreasing adata transmission delay time that may require maximum 32 ms to be within1 to 3 ms by transmitting urgent data using a retransmission resource inthe case that an urgent event occurs in a user equipment and it isrequired to transmit urgent data.

Through this, according to the present disclosure, there is an effect oftransmitting urgent data faster and safely.

The technical effects of the present disclosure are not limited to thetechnical effects described above, and other technical effects notmentioned herein may be understood to those skilled in the art from thedescription below.

DESCRIPTION OF DRAWINGS

The accompanying drawings included as part of the detailed descriptionin order to help understanding of the present invention provideembodiments of the present invention and describe the technicalcharacteristics of the present invention along with the detaileddescription.

FIG. 1 illustrates an example of a network structure of an evolveduniversal terrestrial radio access network (E-UTRAN) to which thepresent invention can be applied.

FIG. 2 illustrates a radio interface protocol structure between a UE andan E-UTRAN in the wireless communication system to which the presentinvention can be applied.

FIG. 3 is a diagram for describing physical channels and a generalsignal transmission method using them used in the 3GPP LTE/LTE-A systemto which the present invention can be applied.

FIG. 4 is a diagram showing the structure of a radio frame used in a3GPP LTE/LTE-A system to which the present invention can be applied.

FIG. 5 shows an example of a resource grid for one downlink slot in thewireless communication system to which the present invention can beapplied.

FIG. 6 shows a structure of a downlink subframe in the wirelesscommunication system to which the present invention can be applied.

FIG. 7 shows a structure of an uplink subframe in the wirelesscommunication system to which the present invention can be applied.

FIG. 8 illustrates the MAC PDU used in the MAC entity in the wirelesscommunication system to which the present invention can be applied.

FIG. 9 and FIG. 10 illustrate the sub-header of the MAC PDU in thewireless communication system to which the present invention can beapplied.

FIG. 11 illustrates formats of the MAC control elements in order toreport the buffer state in the wireless communication system to whichthe present invention can be applied.

FIG. 12 illustrates a UL resource allocation procedure of a UE in thewireless communication system to which the present application can beapplied.

FIG. 13 illustrates an example of a random access procedure to whichpresent application can be applied.

FIG. 14 illustrates an example of a type in which PUCCH formats aremapped to a PUCCH region of an uplink physical resource block in thewireless communication system to which the present invention may beapplied.

FIG. 15 shows the structure of an ACK/NACK channel in the case of acommon CP in a wireless communication system to which an embodiment ofthe present invention may be applied.

FIG. 16 illustrates an example of asynchronous HARQ operation indownlink.

FIG. 17 illustrates an example of synchronous HARQ operation indownlink.

FIG. 18 is a diagram illustrating an example of DCI format 0.

FIG. 19 is a block diagram illustrating a structure of a PDCCH.

FIG. 20 illustrates an example of resource mapping of a PDCCH.

FIG. 21 illustrates an example of distributing CCEs across a systemband.

FIG. 22 illustrates an example of PDCCH monitoring.

FIG. 23 is a diagram illustrating an example of a logical channelprioritization in the LTE system.

FIG. 24 illustrates an example of a signal processing procedure of a ULshared channel which is a transport channel in a wireless communicationsystem to which the present invention may be applied.

FIGS. 25 and 26 are diagrams illustrating an example of a method fortransmitting actual data through scheduling request and BSR procedure.

FIG. 27 is a diagram illustrating an example of a method fortransmitting actual data through RACH procedure.

FIG. 28 is a diagram illustrating an example of a method fortransmitting UL data quickly by using a retransmission resource proposedin the present disclosure.

FIG. 29 is a diagram illustrating a problem that may occur in a methodfor transmitting urgent data by preempting a retransmission resource.

FIG. 30 is a diagram illustrating an example of a MAC PDU formatincluding PHY header proposed in the present disclosure.

FIG. 31 is a flowchart illustrating an example of a decoding method of atransport block including a PHY header proposed in the presentdisclosure.

FIG. 32 illustrates a CRC check procedure in the case that TBsegmentation does not occur for the data transmitted by a UE.

FIG. 33 is a flowchart illustrating another example of a method fordecoding a transport block through new CRC check proposed in the presentdisclosure.

FIG. 34 is a diagram illustrating an example of a method for mapping aresource element (RE) for NDI proposed in the present disclosure.

FIG. 35 is a diagram illustrating an example of a HARQ operation methodin the case that HARQ process is not performed for a UL datatransmission through a preemption resource proposed in the presentdisclosure.

FIG. 36 is a diagram illustrating an example of a HARQ operation methodin the case that HARQ is performed for new data transmitted using aretransmission resource proposed in the present disclosure.

FIG. 37 is a diagram illustrating an example of a HARQ operation methodin the case that HARQ is performed for new data transmitted using aretransmission resource proposed in the present disclosure.

FIG. 38 illustrates a block diagram of a wireless communicationapparatus to which the methods proposed in the present disclosure may beapplied.

BEST MODE FOR INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description set forth below in connection withthe appended drawings is a description of exemplary embodiments and isnot intended to represent the only embodiments through which theconcepts explained in these embodiments can be practiced. The detaileddescription includes details for the purpose of providing anunderstanding of the present invention. However, it will be apparent tothose skilled in the art that these teachings may be implemented andpracticed without these specific details.

In some instances, known structures and devices are omitted, or areshown in block diagram form focusing on important features of thestructures and devices, so as not to obscure the concept of the presentinvention.

In the embodiments of the present invention, the enhanced Node B (eNodeB or eNB) may be a terminal node of a network, which directlycommunicates with the terminal. In some cases, a specific operationdescribed as performed by the eNB may be performed by an upper node ofthe eNB. Namely, it is apparent that, in a network comprised of aplurality of network nodes including an eNB, various operationsperformed for communication with a terminal may be performed by the eNB,or network nodes other than the eNB. The term ‘eNB’ may be replaced withthe term ‘fixed station’, ‘base station (BS)’, ‘Node B’, ‘basetransceiver system (BTS),’, ‘access point (AP)’, etc. The term ‘userequipment (UE)’ may be replaced with the term ‘terminal’, ‘mobilestation (MS)’, ‘user terminal (UT)’, ‘mobile subscriber station (MSS)’,‘subscriber station (SS)’, ‘Advanced Mobile Station (AMS)’, ‘Wirelessterminal (WT)’, ‘Machine-Type Communication (MTC) device’,‘Machine-to-Machine (M2M) device’, Device-to-Device (D2D) device′,wireless device, etc.

In the embodiments of the present invention, “downlink (DL)” refers tocommunication from the eNB to the UE, and “uplink (UL)” refers tocommunication from the UE to the eNB. In the downlink, transmitter maybe a part of eNB, and receiver may be part of UE. In the uplink,transmitter may be a part of UE, and receiver may be part of eNB.

Specific terms used for the embodiments of the present invention areprovided to aid in understanding of the present invention. Thesespecific terms may be replaced with other terms within the scope andspirit of the present invention.

The embodiments of the present invention can be supported by standarddocuments disclosed for at least one of wireless access systems,Institute of Electrical and Electronics Engineers (IEEE) 802, 3rdGeneration Partnership Project (3GPP), 3GPP Long Term Evolution (3GPPLTE), LTE-Advanced (LTE-A), and 3GPP2. Steps or parts that are notdescribed to clarify the technical features of the present invention canbe supported by those documents. Further, all terms as set forth hereincan be explained by the standard documents.

Techniques described herein can be used in various wireless accesssystems such as Code Division Multiple Access (CDMA), Frequency DivisionMultiple Access (FDMA), Time Division Multiple Access (TDMA), OrthogonalFrequency Division Multiple Access (OFDMA), Single Carrier-FrequencyDivision Multiple Access (SC-FDMA), ‘non-orthogonal multiple access(NOMA)’, etc. CDMA may be implemented as a radio technology such asUniversal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may beimplemented as a radio technology such as Global System for Mobilecommunications (GSM)/General Packet Radio Service (GPRS)/Enhanced DataRates for GSM Evolution (EDGE). OFDMA may be implemented as a radiotechnology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Evolved-UTRA (E-UTRA) etc. UTRA is a part of Universal MobileTelecommunication System (UMTS). 3GPP LTE is a part of Evolved UMTS(E-UMTS) using E-UTRA. 3GPP LTE employs OFDMA for downlink and SC-FDMAfor uplink. LTE-A is an evolution of 3GPP LTE.

For clarity, this application focuses on the 3GPP LTE/LTE-A system.However, the technical features of the present invention are not limitedthereto.

General System to which the Present Invention May be Applied

FIG. 1 illustrates a schematic structure a network structure of anevolved universal mobile telecommunication system (E-UTRAN) to which thepresent invention can be applied.

An E-UTRAN system is an evolved version of the UTRAN system. Forexample, the E-UTRAN may be also referred to as an LTE/LTE-A system.

The E-UTRAN consists of eNBs, providing the E-UTRA user plane andcontrol plane protocol terminations towards the UE. The eNBs areinterconnected with each other by means of the X2 interface. The X2 userplane interface (X2-U) is defined between eNBs. The X2-U interfaceprovides non guaranteed delivery of user plane packet data units (PDUs).The X2 control plane interface (X2-CP) is defined between two neighboureNBs. The X2-CP performs following functions: context transfer betweeneNBs, control of user plane tunnels between source eNB and target eNB,transfer of handover related messages, uplink load management and thelike. Each eNB is connected to User Equipments (UEs) through a radiointerface and is connected to an Evolved Packet Core (EPC) through an S1interface. The S1 user plane interface (S1-U) is defined between the eNBand the serving gateway (S-GW). The S1-U interface provides nonguaranteed delivery of user plane PDUs between the eNB and the S-GW. TheS1 control plane interface (S1-MME) is defined between the eNB and theMME (Mobility Management Entity). The S1 interface performs followingfunctions: EPS (Enhanced Packet System) Bearer Service Managementfunction, NAS (Non-Access Stratum) Signaling Transport function, NetworkSharing Function, MME Load balancing Function and the like. The S1interface supports a many-to-many relation between MMEs/S-GWs and eNBs.

FIG. 2 illustrates the configurations of a control plane and a userplane of a radio interface protocol between the E-UTRAN and a UE in thewireless communication system to which the present invention can beapplied.

FIG. 2(a) shows the respective layers of the radio protocol controlplane, and FIG. 2(b) shows the respective layers of the radio protocoluser plane.

Referring to the FIG. 2, the protocol layers of a radio interfaceprotocol between the E-UTRAN and a UE can be divided into an L1 layer(first layer), an L2 layer (second layer), and an L3 layer (third layer)based on the lower three layers of the Open System Interconnection (OSI)reference model widely known in communication systems. The radiointerface protocol is divided horizontally into a physical layer, a datalink layer, and a network layer, and vertically into a user plane fordata transmission and a control plane for signaling.

The control plane is a passage through which control messages that a UEand a network use in order to manage calls are transmitted. The userplane is a passage through which data (e.g., voice data or Internetpacket data) generated at an application layer is transmitted. Thefollowing is a detailed description of the layers of the control anduser planes in a radio interface protocol.

The control plane is a passage through which control messages that a UEand a network use in order to manage calls are transmitted. The userplane is a passage through which data (e.g., voice data or Internetpacket data) generated at an application layer is transmitted. Thefollowing is a detailed description of the layers of the control anduser planes in a radio interface protocol.

The MAC layer of the second layer provides a service to a Radio LinkControl (RLC) layer, located above the MAC layer, through a logicalchannel. The MAC layer plays a role in mapping various logical channelsto various transport channels. And, the MAC layer also plays a role aslogical channel multiplexing in mapping several logical channels to onetransport channel.

The RLC layer of the second layer supports reliable data transmission.The RLC layer performs segmentation and concatenation on data receivedfrom an upper layer to play a role in adjusting a size of the data to besuitable for a lower layer to transfer the data to a radio section. And,the RLC layer provides three kinds of RLC modes including a transparentmode (TM), an unacknowledged mode (UM) and an acknowledged mode (AM) tosecure various kinds of QoS demanded by each radio bearer (RB). Inparticular, the AM RLC performs a retransmission function throughautomatic repeat and request (ARQ) for the reliable data transfer. Thefunctions of the RLC layer may also be implemented through internalfunctional blocks of the MAC layer. In this case, the RLC layer need notbe present.

A packet data convergence protocol (PDCP) layer of the second layerperforms a header compression function for reducing a size of an IPpacket header containing relatively large and unnecessary controlinformation to efficiently transmit such an IP packet as IPv4 and IPv6in a radio section having a small bandwidth. This enables a header partof data to carry mandatory information only to play a role in increasingtransmission efficiency of the radio section. Moreover, in the LTE/LTE-Asystem, the PDCP layer performs a security function as well. Thisconsists of ciphering for preventing data interception conducted by athird party and integrity protection for preventing data manipulationconducted by a third party.

A Radio Resource Control (RRC) layer located at the bottom of the thirdlayer is defined only in the control plane and is responsible forcontrol of logical, transport, and physical channels in association withconfiguration, re-configuration, and release of Radio Bearers (RBs). TheRB is a logical path that the second layer provides for datacommunication between the UE and the E-UTRAN. To accomplish this, theRRC layer of the UE and the RRC layer of the network exchange RRCmessages. To Configure of Radio Bearers means that the radio protocollayer and the characteristic of channels are defined for certain serviceand that each of specific parameters and operating method are configuredfor certain service. The radio bearer can be divided signaling radiobearer (SRB) and data radio bearer (DRB). The SRB is used as a path fortransmission RRC messages in the control plane, and the DRB is used as apath for transmission user data in the user plane.

A Non-Access Stratum (NAS) layer located above the RRC layer performsfunctions such as session management and mobility management.

One cell of the eNB is set to use a bandwidth such as 1.25, 2.5, 5, 10or 20 MHz to provide a downlink or uplink transmission service to UEs.Here, different cells may be set to use different bandwidths.

Downlink transport channels for transmission of data from the network tothe UE include a Broadcast Channel (BCH) for transmission of systeminformation, a Paging Channel (PCH) for transmission of paging messages,and a downlink Shared Channel (DL-SCH) for transmission of user trafficor control messages. User traffic or control messages of a downlinkmulticast or broadcast service may be transmitted through DL-SCH and mayalso be transmitted through a downlink multicast channel (MCH). Uplinktransport channels for transmission of data from the UE to the networkinclude a Random Access Channel (RACH) for transmission of initialcontrol messages and an uplink SCH (UL-SCH) for transmission of usertraffic or control messages.

Logical channels, which are located above the transport channels and aremapped to the transport channels, include a Broadcast Control Channel(BCCH), a Paging Control Channel (PCCH), a Common Control Channel(CCCH), a dedicated control channel (DCCH), a Multicast Control Channel(MCCH), a dedicated traffic channel (DTCH), and a Multicast TrafficChannel (MTCH).

As an downlink physical channel for transmitting information forwardedon an downlink transport channel to a radio section between a networkand a user equipment, there is a physical downlink shared channel(PDSCH) for transmitting information of DL-SCH, a physical controlformat indicator channel (PDFICH) for indicating the number of OFDMsymbols used for transmitting a physical downlink control channel(PDCCH), a physical HARQ (hybrid automatic repeat request) indicatorchannel (PHICH) for transmitting HARQ ACK (Acknowledge)/NACK(Non-acknowledge) as response to UL transmission or a PDCCH fortransmitting such control information, as DL grant indicating resourceallocation for transmitting a Paging Channel (PCH) and DL-SCH,information related to HARQ, UL grant indicating resource allocation fortransmitting a UL-SCH and like that. As an uplink physical channel fortransmitting information forwarded on an uplink transport channel to aradio section between a network and a user equipment, there is aphysical uplink shared channel (PUSCH) for transmitting information ofUL-SCH, a physical random access channel (PRACH) for transmitting RACHinformation or a physical uplink control channel (PUCCH) fortransmitting such control information, which is provided by first andsecond layers, as HARQ ACK/NACK (Non-acknowledge), scheduling request(SR), channel quality indicator (CQI) report and the like.

The NAS state model is based on a two-dimensional model which consistsof EPS Mobility Management (EMM) states and of EPS Connection Management(ECM) states. The EMM states describe the mobility management statesthat result from the mobility management procedures e.g., Attach andTracking Area Update procedures. The ECM states describe the signalingconnectivity between the UE and the EPC.

In detail, in order to manage mobility of a UE in NAS layers positionedin control planes of the UE and an MME, an EPS mobility managementREGISTERED (EMM-REGISTERED) state and an EMM-DEREGISTERED state may bedefined. The EMM-REGISTERED state and the EMM-DEREGISTERED state may beapplied to the UE and the MME.

The UE is in the EMM deregistered state, like a state in which power ofthe UE is first turned on, and in order for the UE to access a network,a process of registering in the corresponding network is performedthrough an initial access procedure. When the access procedure issuccessfully performed, the UE and the MME transition to anEMM-REGISTERED state.

Also, in order to manage signaling connection between the UE and thenetwork, an EPS connection management CONNECTED (ECM-CONNECTED) stateand an ECM-IDLE state may be defined. The ECM-CONNECTED state and theECM-IDLE state may also be applied to the UE and the MME. The ECMconnection may include an RRC connection established between the UE anda BS and an S1 signaling connection established between the BS and theMME. The RRC state indicates whether an RRC layer of the UE and an RRClayer of the BS are logically connected. That is, when the RRC layer ofthe UE and the RRC layer of the BS are connected, the UE may be in anRRC_CONNECTED state. When the RRC layer of the UE and the RRC layer ofthe BS are not connected, the UE in an RRC_IDLE state.

Here, the ECM and EMM states are independent of each other and when theUE is in EMM-REGISTERED state this does not imply that the user plane(radio and S1 bearers) is established

In E-UTRAN RRC_CONNECTED state, network-controlled UE-assisted handoversare performed and various DRX cycles are supported. In E-UTRAN RRC_IDLEstate, cell reselections are performed and DRX is supported.

The network may recognize the presence of the UE in the ECM-CONNECTEDstate by the cell and effectively control the UE. That is, when the UEis in the ECM-CONNECTED state, mobility of the UE is managed by acommand from the network. In the ECM-CONNECTED state, the network knowsabout a cell to which the UE belongs. Thus, the network may transmitand/or receive data to or from the UE, control mobility such as handoverof the UE, and perform cell measurement on a neighbor cell.

Meanwhile, the network cannot recognize the presence of the UE in theECM-idle state and a core network (CN) manages the UE by the trackingarea, a unit greater than cell. When the UE is in the ECM-idle state,the UE performs discontinuous reception (DRX) set by the NAS using an IDuniquely assigned in a tracking region. That is, the UE may monitor apaging signal at a particular paging opportunity in every UE-specificpaging DRX cycle to receive broadcast of system information and paginginformation. Also, when the UE is in the ECM-idle state, the networkdoes not have context information of the UE.

Thus, the UE in the ECM-idle state may perform a UE-basedmobility-related procedure such as cell selection or cell reselectionwithout having to receive a command from the network. When a location ofthe UE in the ECM-idle state is changed from that known by the network,the UE may inform the network about a location thereof through atracking area update (TAU) procedure.

As described above, in order for the UE to receive a general mobilecommunication service such as voice or data, the UE needs to transitionto an ECM-CONNECTED state. The UE is in the ECM-IDLE state like the casein which power of the UE is first turned on. When the UE is successfullyregistered in the corresponding network through an initial attachprocedure, the UE and the MME transition to an ECM-CONNECTED state.Also, in a case in which the UE is registered in the network but trafficis deactivated so radio resource is not allocated, the UE is in anECM-IDLE state, and when uplink or downlink new traffic is generated inthe corresponding UE, the UE and the MME transition to an ECM-CONNECTEDstate through a service request procedure.

FIG. 3 illustrates physical channels and a view showing physicalchannels used for in the 3GPP LTE/LTE-A system to which the presentinvention can be applied.

When a UE is powered on or when the UE newly enters a cell, the UEperforms an initial cell search operation such as synchronization with aBS in step S301. For the initial cell search operation, the UE mayreceive a Primary Synchronization Channel (P-SCH) and a SecondarySynchronization Channel (S-SCH) from the BS so as to performsynchronization with the BS, and acquire information such as a cell ID.

Thereafter, the UE may receive a physical broadcast channel (PBCH) fromthe BS and acquire broadcast information in the cell. Meanwhile, the UEmay receive a Downlink Reference signal (DL RS) in the initial cellsearch step and confirm a downlink channel state.

The UE which completes the initial cell search may receive a PhysicalDownlink Control Channel (PDCCH) and a Physical Downlink Shared Channel(PDSCH) corresponding to the PDCCH, and acquire more detailed systeminformation in step S302.

Thereafter, the UE may perform a random access procedure in steps S303to S306, in order to complete the access to the BS. For the randomaccess procedure, the UE may transmit a preamble via a Physical RandomAccess Channel (PRACH) (S303), and may receive a message in response tothe preamble via the PDCCH and the PDSCH corresponding thereto (S304).In contention-based random access, a contention resolution procedureincluding the transmission of an additional PRACH (S305) and thereception of the PDCCH and the PDSCH corresponding thereto (S306) may beperformed.

The UE which performs the above-described procedure may then receive thePDCCH/PDSCH (S307) and transmit a Physical Uplink Shared Channel(PUSCH)/Physical Uplink Control Channel (PUCCH) (S308), as a generaluplink/downlink signal transmission procedure.

Control information transmitted from the UE to the BS is collectivelyreferred to as uplink control information (UCI). The UCI includes hybridautomatic repeat and request acknowledgement/negative-acknowledgement(HARQ ACK/NACK), scheduling request (SR), channel quality information(Cal), precoding matrix indicator (PMI), rank indication (RI), etc. Inthe embodiments of the present invention, CQI and/or PMI are alsoreferred to as channel quality control information.

In general, although a UCI is periodically transmitted via a PUCCH inthe LTE system, this may be transmitted through a PUSCH if controlinformation and traffic data are simultaneously transmitted. Inaddition, a UCI may be aperiodically transmitted via a PUSCH accordingto a network request/instruction.

FIG. 4 is a diagram showing the structure of a radio frame used in a3GPP LTE system to which the present invention can be applied.

In a cellular OFDM radio packet communication system, uplink/downlinkdata packet transmission is performed in subframe units and one subframeis defined as a predetermined duration including a plurality of OFDMsymbols. The 3GPP LTE standard supports a type-1 radio frame structureapplicable to frequency division duplex (FDD) and a type-2 radio framestructure applicable to time division duplex (TDD). According to the FDDscheme, the UL transmission and the DL transmission are performed byoccupying different frequency bandwidths. According to the TDD scheme,the UL transmission and the DL transmission are performed on respectivetimes different from each other while occupying the same frequencybandwidth. The channel response in the TDD scheme is substantiallyreciprocal. This signifies that the DL channel response and the ULchannel response are about the same in a given frequency domain.Accordingly, there is a merit that the DL channel response can beobtained from the UL channel response in wireless communication systemsbased on the TDD. In the TDD scheme, since entire frequency bandwidth istimely divided in the UL transmission and the DL transmission, the DLtransmission by an eNB and the UL transmission by a UE may not beperformed simultaneously. In the TDD system in which the UL transmissionand the DL transmission are distinguished by a unit of subframe, the ULtransmission and the DL transmission are performed in differentsubframes.

FIG. 4(a) shows the structure of the type-1 radio frame. A downlinkradio frame includes 10 subframes and one subframe includes two slots ina time domain. A time required to transmit one subframe is referred toas a transmission time interval (TTI). For example, one subframe has alength of 1 ms and one slot has a length of 0.5 ms. One slot includes aplurality of OFDM symbols in a time domain and includes a plurality ofresource blocks (RBs) in a frequency domain. In the 3GPP LTE system,since OFDMA is used in the downlink, an OFDM symbol indicates one symbolperiod. The OFDM symbol may be referred to as an SC-FDMA symbol orsymbol period. A RB as a resource allocation unit may include aplurality of consecutive subcarriers in one slot.

The number of OFDM symbols included in one slot may be changed accordingto the configuration of cyclic prefix (CP). CP includes an extended CPand a normal CP. For example, if OFDM symbols are configured by thenormal CP, the number of OFDM symbols included in one slot may be 7. IfOFDM symbols are configured by the extended CP, since the length of oneOFDM symbol is increased, the number of OFDM symbols included in oneslot is less than the number of OFDM symbols in case of the normal CP.In case of the extended CP, for example, the number of OFDM symbolsincluded in one slot may be 6. In the case where a channel state isunstable, such as the case where a UE moves at a high speed, theextended CP may be used in order to further reduce inter-symbolinterference.

In case of using the normal CP, since one slot includes seven OFDMsymbols, one subframe includes 14 OFDM symbols. At this time, a maximumof three first OFDM symbols of each subframe may be allocated to aphysical downlink control channel (PDCCH) and the remaining OFDM symbolsmay be allocated to a physical downlink shared channel (PDSCH).

FIG. 4(b) shows the structure of the type-2 radio frame. The type-2radio frame includes two half frames and each half frame includes fivesubframes, a downlink pilot time slot (DwPTS), a guard period (GP) andan uplink pilot time slot (UpPTS). From among these, one subframeincludes two slots. The DwPTS is used for initial cell search,synchronization or channel estimation of a UE. The UpPTS is used forchannel estimation of a BS and uplink transmission synchronization of aUE. The GP is used to eliminate interference generated in the uplink dueto multi-path latency of a downlink signal between the uplink and thedownlink.

The structure of the radio frame is only exemplary and the number ofsubframes included in the radio frame, the number of slots included inthe subframe, or the number of symbols included in the slot may bevariously changed.

FIG. 5 shows an example of a resource grid for one downlink slot in thewireless communication system to which the present invention can beapplied.

Referring to the FIG. 5, the downlink slot includes a plurality of OFDMsymbols in a time domain. It is described herein that one downlink slotincludes 7 OFDMA symbols and one resource block includes 12 subcarriersfor exemplary purposes only, and the present invention is not limitedthereto.

Each element on the resource grid is referred to as a resource element,and one resource block includes 12×7 resource elements. The resourceelement on the resource grid may be identified by an index pair (k, l)in the slot. Here, k (k=0, . . . , NRB×12−1) denotes an index ofsubcarrier in the frequency domain, and l (l=0, . . . , 6) denotes anindex of symbol in the time domain. The number NDL of resource blocksincluded in the downlink slot depends on a downlink transmissionbandwidth determined in a cell.

FIG. 6 shows a structure of a downlink subframe in the wirelesscommunication system to which the present invention can be applied.

Referring to the FIG. 6, a maximum of three OFDM symbols located in afront portion of a first slot in a subframe correspond to a controlregion to be assigned with control channels. The remaining OFDM symbolscorrespond to a data region to be assigned with physical downlink sharedchannels (PDSCHs).

Examples of downlink control channels used in the 3GPP LTE include aphysical control format indicator channel (PCFICH), a physical downlinkcontrol channel (PDCCH), a physical hybrid-ARQ indicator channel(PHICH), etc. The PCFICH transmitted in a 1st OFDM symbol of a subframecarries information regarding the number of OFDM symbols (i.e., a sizeof a control region) used for transmission of control channels in thesubframe. Control information transmitted over the PDCCH is referred toas downlink control information (DCI). The DCI transmits uplink resourceassignment information, downlink resource assignment information, anuplink transmit power control (TPC) command for any UE groups, etc. ThePHICH carries an acknowledgement (ACK)/not-acknowledgement (NACK) signalfor an uplink hybrid automatic repeat request (HARQ). That is, theACK/NACK signal for uplink data transmitted by a UE is transmitted overthe PHICH.

A BS determines a PDCCH format according to DCI to be transmitted to aUE, and attaches a cyclic redundancy check (CRC) to control information.The CRC is masked with a unique identifier (referred to as a radionetwork temporary identifier (RNTI)) according to an owner or usage ofthe PDCCH. If the PDCCH is for a specific UE, a unique identifier (e.g.,cell-RNTI (C-RNTI)) of the UE may be masked to the CRC. Alternatively,if the PDCCH is for a paging message, a paging indication identifier(e.g., paging-RNTI (P-RNTI)) may be masked to the CRC. If the PDCCH isfor system information, a system information identifier (e.g., systeminformation-RNTI (SI-RNTI)) may be masked to the CRC. To indicate arandom access response that is a response for transmission of a randomaccess preamble of the UE, a random access-RNTI (RA-RNTI) may be maskedto the CRC.

FIG. 7 shows a structure of an uplink subframe in the wirelesscommunication system to which the present invention can be applied.

Referring to the FIG. 7, the uplink subframe can be divided in afrequency domain into a control region and a data region. The controlregion is allocated with a physical uplink control channel (PUCCH) forcarrying uplink control information. The data region is allocated with aphysical uplink shared channel (PUSCH) for carrying user data. In caseof being indicated from higher layer, UE can simultaneously transmit thePUCCH and the PUSCH.

The PUCCH for one UE is allocated to an RB pair in a subframe. RBsbelonging to the RB pair occupy different subcarriers in respective twoslots. This is called that the RB pair allocated to the PUCCH isfrequency-hopped in a slot boundary.

Physical Downlink Control Channel (PDCCH)

The control information transmitted through the PDCCH is referred to asa downlink control indicator (DCI). In the PDCCH, a size and use of thecontrol information are different according to a DCI format. Inaddition, a size of the control information may be changed according toa coding rate.

Table 1 represents the DCI according to the DCI format.

TABLE 1 DCI format Objectives 0 Scheduling of PUSCH 1 Scheduling of onePDSCH codeword 1A Compact scheduling of one PDSCH codeword 1BClosed-loop single-rank transmission 1C Paging, RACH response anddynamic BCCH 1D MU-MIMO 2 Scheduling of rank-adapted closed-loop spatialmultiplexing mode 2A Scheduling of rank-adapted open-loop spatialmultiplexing mode 3 TPC commands for PUCCH and PUSCH with 2 bit poweradjustments 3A TPC commands for PUCCH and PUSCH with single bit poweradjustments 4 the scheduling of PUSCH in one UL cell with multi-antennaport transmission mode

Referring to Table 1, the DCI format includes format 0 for the PUSCHscheduling, format 1 for scheduling of one PDSCH codeword, format 1A forcompact scheduling of one PDSCH codeword, format 10 for very compactscheduling of the DL-SCH, format 2 for PDSCH scheduling in a closed-loopspatial multiplexing mode, format 2A for PDSCH scheduling in anopen-loop spatial multiplexing mode, formats 3 and 3A for transmitting atransmission power control (TPC) command for a UL channel, and format 4for PUSCH scheduling within one UL cell in a multiple antenna porttransmission mode.

The DCI format 1A may be used for PDSCH scheduling whichevertransmission mode is configured to a UE.

Such DCI formats may be independently applied to each UE, and the PDCCHsof several UEs may be simultaneously multiplexed in one subframe. ThePDCCH is comprised of an aggregation of one or a few continuous controlchannel elements (CCEs). The CCE is a logical allocation unit used forproviding a coding rate according to a state of radio channel to thePDCCH. The CCE is referred to as a unit that corresponds to nine sets ofresource element group (REG) which is comprised of four resourceelements. An eNB may use {1, 2, 4, 8} CCEs for constructing one PDCCHsignal, and this {1, 2, 4, 8} is called a CCE aggregation level. Thenumber of CCE used for transmitting a specific PDCCH is determined bythe eNB according to the channel state. The PDCCH configured accordingto each UE is mapped with being interleaved to a control channel regionof each subframe by a CCE-to-RE mapping rule. A location of the PDCCHmay be changed according to the number of OFDM symbols for the controlchannel, the number of PHICH group, a transmission antenna, a frequencyshift, etc.

As described above, a channel coding is independently performed for thePDCCH of each multiplexed UE, and the cyclic redundancy check (CRC) isapplied. By masking each UE ID to CRC, the UE may receive its PDCCH.However, in the control region allocated in a subframe, the eNB does notprovide information on where the PDCCH that corresponds to the UE is.Since the UE is unable to know on which position its PDCCH istransmitted with which CCE aggregation level and DCI format in order toreceive the control channel transmitted from the eNB, the UE finds itsown PDCCH by monitoring a set of PDCCH candidates in a subframe. This iscalled a blind decoding (BD). The blind decoding may also be called ablind detection or a blind search. The blind decoding signifies a methodof verifying whether the corresponding PDCCH is its control channel bychecking CRC errors, after the UE de-masks its UE ID in CRC part.

Buffer Status Reporting (BSR)

FIG. 8 illustrates the MAC PDU used in the MAC entity in the wirelesscommunication system to which the present invention can be applied.

Referring to FIG. 8, the MAC PDU includes a MAC header, at least one MACservice data unit (SDU) and at least one control element, additionallymay include padding. In some cases, at least one of the MAC SDUs and theMAC control elements may not be included in the MAC PDU.

As an example of FIG. 8, it is common that the MAC control elements arelocated ahead of the MAC SDUs. And the size of MAC control elements maybe fixed or changeable. In case that the size of MAC control elements ischangeable, it may be determined through an extended bit whether thesize of MAC control elements is extended. The size of MAC SDU may bealso variable.

The MAC header may include at least one sub-header. In this time, atleast one sub-header that is included in the MAC header is respectivelycorresponding to the MAC SDUs, the MAC control elements and the padding,and the order of the sub-header is same as the arrangement order of thecorresponding elements. For example, as an example of FIG. 8, if thereare included MAC control element 1, MAC control element 2, a pluralityof MAC SDUs and padding in the MAC PDU, in the MAC header, the followingmay be arranged in order as a sub-header corresponding to the MACcontrol element 1, a sub-header corresponding to the MAC control element2, a plurality of sub-headers corresponding to a plurality of MAC SDUsrespectively and a sub-header corresponding to the padding.

Sub-headers included in the MAC header, as an example of FIG. 8, sixheader fields may be included. Particularly, the sub-header may includesix header fields of R/R/E/LCID/F/L.

For the sub-header corresponding to the very last one among thesub-header corresponding to the MAC control element of fixed size anddata fields included in the MAC PDU, as an example illustrated in FIG.8, the sub-header that is included four header fields may be used. Incase that the sub-header includes four fields like this, the four fieldsmay be R/R/E/LCID.

FIG. 9 and FIG. 10 illustrate the sub-header of the MAC PDU in thewireless communication system to which the present invention can beapplied.

Each field is described as below with reference to FIG. 9 and FIG. 10.

1) R: Reserved bit, which is not used.

2) E: Extended field, which represents whether the elementscorresponding to the sub-header are extended. For example, in case thatE field is ‘0’, the element corresponding to the sub-header isterminated without any repeat, and in case that E field is ‘1’, theelement corresponding to the sub-header is repeated once more and may beextended by twice in the length.

LCID: Logical channel identification field identifies a logical channelcorresponding to the relevant MAC SDU or identifies a type of therelevant MAC control element and padding. If the MAC SDU is associatedwith the sub-header, it may show which logical channel the MAC SDU iscorresponding to, and if the MAC control element is associated with thesub-header, it may show what the MAC control element is.

Table 2 represents the value of LCID for the DL-SCH

TABLE 2 Index LCID values 00000 CCCH 00001-01010 Identity of the logicalchannel 01011-11001 Reserved 11010 Long DRX Command 11011Activation/Deactivation 11100 UE Contention Resolution Identity 11101Timing Advance Command 11110 DRX Command 11111 Padding

Table 3 represents the value of LCID for the UL-SCH

TABLE 3 Index LCID values 00000 CCCH 00001-01010 Identity of the logicalchannel 01011-11000 Reserved 11001 Extended Power Headroom Report 11010Power Headroom Report 11011 C-RNTI 11100 Truncated BSR 11101 Short BSR11110 Long BSR 11111 Padding

In LTE/LTE-A system, the UE may report the buffer state of its own tothe network by configuring one of the index value among truncated BSR,short BSR, and long BSR in the LCID field.

The relationship of mapping between the index and the LCID valueillustrated in Table 2 and Table 3 is exemplified for the convenience ofthe descriptions, but the present invention is not limited thereto.

4) F: Format field, which represents the size of L field.

5) L: Length field, which represents the size of MAC SDU and MAC controlelement corresponding to the sub-header. If the size of MAC SDU or MACcontrol element corresponding to the sub-header is equal to or less than127 bits, the 7-bit L field is used (FIG. 9 (a)), otherwise, the 15-bitL field may be used (FIG. 9 (b)). In case that the size of MAC controlelement is changeable, the size of MAC control element may be defined bythe L field. In case that the size of MAC control element is fixed, thesize of MAC control element may be determined without the size of MACcontrol element being defined by the L field, accordingly the F and Lfield may be omitted as shown in FIG. 10.

FIG. 11 illustrates formats of the MAC control elements in order toreport the buffer state in the wireless communication system to whichthe present invention can be applied.

In case of the truncated BSR and short BSR being defined in the LCIDfield of sub-header, the MAC control element corresponding to thesub-header, as shown in FIG. 11 (a), may be configured to include onelogical channel group identification (LCG ID) field and one buffer sizefield indicating the buffer state of the LCG. The LCG ID field is foridentifying the logical channel group that is required to report thebuffer state, which may have the size of 2 bits.

The buffer size field is used for identifying the total amount ofavailable data from the all logical channels that are included in theLCG. The available data includes all the data that are going to betransmitted from the RLC layer and the PDCP layer, and the amount ofdata is represented in byte. In this time, the size of RLC header andMAC header may be excluded when calculating the amount of data. Thebuffer size field may be 6 bits.

In case of the extended BSR being defined in the LCID field ofsub-header, the MAC control element corresponding to the sub-header, asshown in FIG. 11 (b), may include four buffer size fields indicating thebuffer state of four groups having 0 to 3 LCG IDs. Each of the buffersize fields may be used for identifying the total amount of availabledata from different logical channel groups.

Uplink Resource Allocation Procedure

In 3GPP LTE/LTE-A system, in order to maximize resource utilization, thedata transmission and reception method based on scheduling of an eNB isused. This signifies that if there are data to transmit by a UE, the ULresource allocation is preferentially requested to the eNB, and the datamay be transmitted using only UL resources allocated by the eNB.

FIG. 12 illustrates a UL resource allocation procedure of a UE in thewireless communication system to which the present application can beapplied.

For effective utilization of the UL radio resources, an eNB should knowwhich sorts and what amount of data to be transmitted to the UL for eachUE. Accordingly, the UE itself may forward the information of UL data totransmit, and the eNB may allocate the UL resources to the correspondingUE based on this. In this case, the information of the UL data that theUE forwards to the eNB is the quality of UL data stored in its buffer,and this is referred to as a buffer status report (BSR). The BSR istransmitted using a MAC control element in case that the resources onthe PUSCH in current TTI are allocated to the UE and the reporting eventis triggered.

FIG. 12(a) exemplifies a UL resource allocation procedure for actualdata in case that the UL radio resources for the buffer status reporting(BSR) are not allocated to a UE. That is, for a UE that switches a stateof active mode in the DRX mode, since there is no data resourceallocated beforehand, the resource for UL data should be requestedstarting from the SR transmission through the PUCCH, in this case, theUL resource allocation procedure of 5 steps is used.

Referring to FIG. 12(a), the case that the PUSCH resource fortransmitting the BSR is not allocated to a UE is illustrated, and the UEtransmits the scheduling request (SR) to an eNB first in order to beallocated with the PUSCH resources (step, S1201).

The scheduling request (SR) is used to request in order for the UE to beallocated with the PUSCH resource for UL transmission in case that thereporting event is occurred but the radio resource is not scheduled onthe PUSCH in current TTI. That is, the UE transmits the SR on the PUCCHwhen the regular BSR is triggered but does not have the UL radioresource for transmitting the BSR to the eNB. The UE transmits the SRthrough the PUCCH or starts the random access procedure according towhether the PUCCH resources for the SR are configured. In particular,the PUCCH resources in which the SR can be transmitted may be determinedas a combination of the PRB through which the SR is transmitted, thecyclic shift (CS) applied to a basic sequence (e.g., ZC sequence) forspread in frequency domain of the SR and an orthogonal code (OC) forspread in time domain of the SR. Additionally, the SR periodicity andthe SR subframe offset information may be included. The PUCCH resourcesthrough which the SR can be transmitted may be configured by a higherlayer (e.g., the RRC layer) in UE-specific manner.

When a UE receives the UL grant for the PUSCH resources for BSRtransmission from an eNB (step, S1203), the UE transmits the triggeredBSR through the PUSCH resources which are allocated by the UL grant(step, S1205).

The eNB verifies the quality of data that the UE actually transmit tothe UL through the BSR, and transmits the UL grant for the PUSCHresources for actual data transmission to the UE (step, S1207). The UEthat receives the UL grant for actual data transmission transmits theactual UL data to the eNB through the PUSCH resources (step, S1209).

FIG. 12(b) exemplifies the UL resource allocation procedure for actualdata in case that the UL radio resources for the BSR are allocated to aUE.

Referring to FIG. 12(b), the case that the PUSCH resources for BRStransmission are already allocated to a UE is illustrated. In the case,the UE transmits the BSR through the allocated PUSCH resources, andtransmits a scheduling request to an eNB (step, S1211). Subsequently,the eNB verifies the quality of data to be transmitted to the UL by theUE through the BSR, and transmits the UL grant for the PUSCH resourcesfor actual data transmission to the UE (step, S1213). The UE thatreceives the UL grant for actual data transmission transmits the actualUL data to the eNB through the allocated PUSCH resources (step, S1215).

FIG. 13 is a diagram for describing a latency in C-plane required in3GPP LTE-A to which the present invention can be applied.

Referring to FIG. 13, 3GPP LTE-A requests a transition time from an idlemode (a state that IP address is allocated) to a connected mode to beless than 50 ms. In this time, the transition time includes aconfiguration time (except latency for transmitting S1) in a user plane(U-plane). In addition, a transition time from a dormant state to anactive state in the connection mode is requested to be less than 10 ms.

The transition from the dormant state to the active state may occur in 4scenarios as follows.

-   -   Uplink initiated transition, synchronized    -   Uplink initiated transition, unsynchronized    -   Downlink initiated transition, synchronized    -   Downlink initiated transition, unsynchronized

Random Access Channel (RACH) Procedure

FIGS. 13a and 13b illustrate one example of a random access procedure inthe LTE system.

The random access procedure is carried out during initial connection inthe RRC_IDLE state, initial connection after radio link failure,handover which requires the random access procedure, and upon occurrenceof uplink or downlink data requiring the random access procedure whilein the RRC_CONNECTED state. Part of the RRC message such as the RRCconnection request message, cell update message, and UTRAN registrationarea (URA) update message is also transmitted through the random accessprocedure. Logical channels such as a common control channel (CCCH),dedicated control channel (DCCH), and dedicated traffic channel (DTCH)can be mapped to a physical channel, random access channel (RACH). TheRACH is mapped to a physical channel, physical random access channel(PRACH).

If the MAC layer of the UE commands the UE's physical layer to performPRACH transmission, the UE's physical layer first selects one accessslot and one signature and transmits a PRACH preamble through uplinktransmission. The random access procedure is divided into acontention-based random access procedure and a non-contention basedrandom access procedure.

FIG. 13a illustrates one example of a contention-based random accessprocedure, and FIG. 13b illustrates one example of a non-contentionbased random access procedure.

First, the contention-based random access procedure will be describedwith reference to FIG. 13 a.

The UE receives information about random access from the eNB throughsystem information and stores the received information. Afterwards, incase random access is needed, the UE transmits a random access preamble(which is also called a message 1) to the eNB S1301.

If the eNB receives a random access preamble from the UE, the eNBtransmits a random access response message (which is also called amessage 2) to the UE S1302. More specifically, downlink schedulinginformation about the random access response message, being CRC-maskedwith a random access-ratio network temporary identifier (RA-RNTI), canbe transmitted on an L1 or L2 control channel (PDCCH). The UE, which hasreceived a downlink scheduling signal masked with an RA-RNTI, canreceive the random access response message from a physical downlinkshared channel (PDSCH) and decode the received message. Afterwards, theUE checks the random access response message as to whether random accessresponse information for the UE exists.

The UE can determine existence of random access response information bychecking existence of a random access preamble ID (RAID) with respect tothe preamble that the UE has transmitted.

The random access response information includes timing alignment (TA)indicating timing offset information for synchronization, radio resourceallocation information used for uplink transmission, and a temporaryC-RNTI for identifying UEs.

If receiving random access response information, the UE carries outuplink transmission (which is also called a message 3) to an uplinkshared channel (UL-SCH) according to radio resource allocationinformation included in the response information S1303. At this time,uplink transmission may be described as scheduled transmission.

After receiving the uplink transmission from the UE, the eNB transmits amessage for contention resolution (which is also called a message 4) tothe UE through a downlink shared channel (DL-SCH) S1304.

Next, a non-contention based random access procedure will be describedwith reference to FIG. 13 b.

Before the UE transmits a random access preamble, the eNB allocates anon-contention random access preamble to the UE S1311.

The non-contention random access preamble can be allocated through ahandover command or dedicated signaling such as signaling through thePDCCH. In case non-contention random access preamble is allocated to theUE, the UE transmits the allocated non-contention random access preambleto the eNB S1312.

Afterwards, similarly to the S1302 step of the contention-based randomaccess procedure, the UE can transmit a random access response (which isalso called a message 2) to the UE S1313.

Although the HARQ is not applied for a random access response during therandom access procedure described above, the HARQ can be applied foruplink transmission with respect to a random access response or amessage for contention resolution. Therefore, the UE doesn't have totransmit ACK or NACK signal for the case of the random access response.

Physical Uplink Control Channel (PUCCH)

Uplink control information (UCI) transmitted through a PUCCH may includea scheduling request (SR), HARQ ACK/NACK information and downlinkchannel measurement information.

The HARQ ACK/NACK information may be generated depending on whether adownlink data packet on a PDSCH has been successfully decoded or not. Inan existing wireless communication system, 1 bit is transmitted asACK/NACK information with respect to the transmission of downlink singlecodeword, and 2 bits are transmitted as ACK/NACK information withrespect to the transmission of downlink 2 codewords.

The channel measurement information refers to feedback informationrelated to a multiple input multiple output (MIMO) scheme, and mayinclude a channel quality indicator (Cal), a precoding matrix index(PMI) and a rank indicator (RI). Pieces of these channel measurementinformation may be collectively expressed as a CQI.

For the transmission of a CQI, 20 bits may be used per subframe.

A PUCCH may be modulated using binary phase shift keying (BPSK) schemeand a quadrature phase shift keying (QPSK) scheme. Control informationof a plurality of UEs may be transmitted through a PUCCH. If codedivision multiplexing (CDM) is performed to distinguish the signals ofUEs, a constant amplitude zero autocorrelation (CAZAC) sequence of alength 12 is chiefly used. The CAZAC sequence has a characteristic inthat it maintains constant amplitude in a time domain and a frequencydomain, and thus has a property suitable for increasing coverage bylowering the peak-to-average power ratio (PAPR) or cubic metric (CM) ofa UE. Furthermore, ACK/NACK information for downlink data transmissiontransmitted through a PUCCH is covered using orthogonal sequence ororthogonal cover (OC).

Furthermore, control information transmitted on a PUCCH may bedistinguished using a cyclically shifted sequence having a differentcyclic shift (CS) value. The cyclically shifted sequence may begenerated by cyclically shifting a base sequence by a specific CSamount. The specific CS amount is indicated by a CS index. The number ofavailable cyclic shifts may be different depending on the latency spreadof a channel. A variety of types of sequences may be used as the basesequence, and the aforementioned CAZAC sequence is an example thereof.

Furthermore, the amount of control information which may be transmittedby a UE in one subframe may be determined depending on the number ofSC-FDMA symbols which may be used to send control information (i.e.,SC-FDMA symbols other than an SC-FDMA symbol used in the transmission ofa reference signal (RS) for the coherent detection of a PUCCH.

In the 3GPP LTE system, a PUCCH is defined as a total of differentformats depending on transmitted control information, a modulationscheme and the amount of control information. The attributes of uplinkcontrol information (UCI) transmitted may be summarized as in Table 4below depending on each PUCCH format.

TABLE 4 PUCCH # of bits per format Modulation scheme sub-frame Usage1(x) N/A N/A Scheduling Request 1a BPSK  1 1-bit A/N + SR 1b QPSK  22-bits A/N + SR 2x QPSK 20 CQI or CQI + A/N 2a QPSK + BPSK 20 + 1 CQI +1-bit A/N 2b QPSK + BPSK 20 + 2 CQI + 2-bits A/N 3 QPSK 48 A/N + SR

PUCCH format 1(x) is used for SR-only transmission. In the case ofSR-only transmission, a waveform which is not modulated is applied.

The PUCCH format 1a or 1b is used to transmit HARQ ACK/NACK. In the casethat HARQ ACK/NACK is solely transmitted in a specific subframe, PUCCHformat 1a or 1b may be used. Alternatively, HARQ ACK/NACK and an SR maybe transmitted in the same subframe using PUCCH format 1a or 1b.

As described above, PUCCH format 1a or 1b may be used for the case thatan SR is transmitted together with HARQ ACK/NACK. A PUCCH index for HARQACK/NACK is implicitly determined from a lower CCE index which is mappedfor the related PDCCH.

Multiplexing Negative SR with A/N

: A UE transmits A/N to A/N PUCCH resource which is mapped to the lowestCCE index used in a PDCCH.

Multiplexing Positive SR with A/N

: A UE transmits A/N using the SR PUCCH resource allocated from an eNB.

PUCCH format 2 is used for the transmission of a CQI, and PUCCH format2a or 2b is used for the transmission of a CQI and HARQ ACK/NACK.

In the case of the extended CP, PUCCH format 2 may also be used for thetransmission of a CQI and HARQ ACK/NACK.

An SR resource of a UE is setup/released through an RRC ConnectionReconfig. (Radio Resource Config. Dedicated (Physical config. Dedicated(SR config))).

Here, SR resource for maximum 2048 UEs is available to be allocated inone subframe. This means that 2048 logical indexes are defined forPUCCH, and the physical resource for PUCCH formats 1 to 3 may be mappedup to 2048 logically.

It is designed that an SR periodicity may be set to 1 ms to 80 msaccording to an SR configuration index in the configuration of SRresource per UE, and an SR subframe offset is also configured accordingto an index.

An SR signaling of a UE is defined to use simple On-Off Keying (O.O.K)scheme, and defined to mean that D(0)=1: Request a PUSCH resource(positive SR), Transmitting nothing: not request to be scheduled(negative SR).

In addition, an SR is designed to use the CAZAC sequence having thelength of 12 and the OC sequences having the length of 3 such that theSR for maximum 36 UEs is able to be allocated through PUCCH 1 RB (in thecase of the Normal CP).

A DMRS position of PUCCH format 1/1a/1b(A/N, SR) will be described indetail below in FIG. 14.

FIG. 14 illustrates an example of a type in which PUCCH formats aremapped to a PUCCH region of an uplink physical resource block in thewireless communication system to which the present invention may beapplied.

In FIG. 14, N_(RB) ^(UL) represents the number of resource blocks in theuplink, and 0, 1, . . . , N_(RB) ^(UL)−1 mean the numbers of physicalresource blocks. Basically, the PUCCH is mapped to both edges of anuplink frequency block. As illustrated in FIG. 14, PUCCH format 2/2a/2bis mapped to a PUCCH region expressed as m=0, 1 and this may beexpressed in such a manner that PUCCH format 2/2a/2b is mapped toresource blocks positioned at a band edge. Furthermore, both PUCCHformat 2/2a/2b and PUCCH format 1/1a/1b may be mixedly mapped to a PUCCHregion expressed as m=2.

Next, PUCCH format 1/1a/1b may be mapped to a PUCCH region expressed asm=3, 4, and 5. The number (N_(RB) ⁽²⁾) of PUCCH RBs which are usable byPUCCH format 2/2a/2b may be indicated to UEs in a cell by broadcastingsignaling.

PUCCH format 2/2a/2b is described. PUCCH format 2/2a/2b is a controlchannel for transmitting channel measurement feedback (CQI, PMI, andRI).

A reporting period of the channel measurement feedbacks (hereinafter,collectively expressed as CQI information) and a frequency unit (or afrequency resolution) to be measured may be controlled by an eNB. In thetime domain, periodic and aperiodic CQI reporting may be supported.PUCCH format 2 may be used for only the periodic reporting and the PUSCHmay be used for aperiodic reporting. In the case of the aperiodicreporting, an eNB may instruct a UE to transmit a scheduling resource onwhich an individual CQI reporting is carried for the uplink datatransmission.

PUCCH Channel Structure

The PUCCH formats 1 a and 1b are described.

In the PUCCH formats 1 a/1b, a symbol modulated using the BPSK or QPSKmodulation scheme is multiplied by a CAZAC sequence of a length 12. Forexample, the results of the multiplication of a modulation symbol d(0)by a CAZAC sequence r(n) (n=0, 1, 2, . . . , N−1) of a length N arey(0), y(1), y(2), . . . , y(N−1). y(0), . . . , y(N−1) symbols may becalled a block of symbols. After a modulation symbol is multiplied by aCAZAC sequence, block-wise spreading using an orthogonal sequence isapplied.

A Hadamard sequence of a length 4 is used for common ACK/NACKinformation, and a discrete Fourier transform (DFT) sequence of a length3 is used for shortened ACK/NACK information and a reference signal.

A Hadamard sequence of a length 2 is used for a reference signal in thecase of an extended CP.

FIG. 15 shows the structure of an ACK/NACK channel in the case of acommon CP in a wireless communication system to which an embodiment ofthe present invention may be applied.

FIG. 15 illustrates the structure of a PUCCH channel for thetransmission of HARQ ACK/NACK without a CQI.

A reference signal (RS) is carried on three contiguous SC-FDMA symbolsthat belong to seven SC-FDMA symbols included in one slot and that arelocated in the middle part, and an ACK/NACK signal is carried on theremaining four SC-FDMA symbols.

In the case of an extended CP, an RS may be carried on two contiguoussymbols in the middle. The number and location of symbols used for an RSmay be different depending on a control channel. The number and locationof symbols used for an ACK/NACK signal associated with the RS may alsobe changed depending on the RS.

Pieces of acknowledgement information (an unscrambled state) of 1 bitand 2 bits may be expressed as one HARQ ACK/NACK modulation symbol usingthe BPSK and QPSK modulation schemes, respectively. Positiveacknowledgement (ACK) may be encoded into “1”, and negativeacknowledgement (NACK) may be encoded into “0.”

2-dimensional spreading is applied in order to improve a multiplexingcapacity when a control signal is transmitted within an allocated band.That is, in order to increase the number of UEs or the number of controlchannels that may be multiplexed, frequency domain spreads and timedomain spreads are applied at the same time.

In order to spread an ACK/NACK signal in the frequency domain, afrequency domain sequence is used as a base sequence. A Zadoff-Chu (ZC)sequence, that is, one of CAZAC sequences, may be used as a frequencydomain sequence. For example, the multiplexing of different UEs ordifferent control channels may be applied by applying a different cyclicshift (CS) to a ZC sequence, that is, a base sequence. The number of CSresources supported in an SC-FDMA symbol for PUCCH RBs for thetransmission of HARQ ACK/NACK is set by a cell-specific higher layersignaling parameter Δ_(shift) ^(PUCCH).

An ACK/NACK signal on which frequency domain spreading has beenperformed is spread in the time domain using orthogonal spreading code.A Walsh-Hadamard sequence or DFT sequence may be used as the orthogonalspreading code. For example, an ACK/NACK signal may be spread usingorthogonal sequences w0, w1, w2 and w3 of a length 4 with respect tofour symbols. Furthermore, an RS is also spread through an orthogonalsequence of a length 3 or a length 2. This is called orthogonal covering(OC).

A plurality of UEs may be multiplexed according to a code divisionmultiplexing (CDM) method using the aforementioned CS resources in thefrequency domain and the aforementioned OC resources in the time domain.That is, the ACK/NACK information and RSs of a large number of UEs onthe same PUCCH RB may be multiplexed.

With respect to such time domain spreading CDM, the number of spreadingcodes supported with respect to ACK/NACK information is limited by thenumber of RS symbols. That is, since the number of RS transmissionSC-FDMA symbols is smaller than that of ACK/NACK informationtransmission SC-FDMA symbols, the multiplexing capacity of an RS issmaller than that of ACK/NACK information.

For example, in the case of a common CP, ACK/NACK information may betransmitted in four symbols. Three orthogonal spreading codes not fourorthogonal spreading codes are used for ACK/NACK information. The reasonfor this is that since the number of RS transmission symbols is limitedto three, only the three orthogonal spreading codes may be used for anRS.

In the case where three symbols are used to send an RS and four symbolsare used to send ACK/NACK information in one slot of a subframe of acommon CP, for example, if six CSs can be used in the frequency domainand three orthogonal cover (OC) resources can be used in the timedomain, HARQ acknowledgement from a total of 18 different UEs may bemultiplexed within one PUCCH RB. In the case where two symbols are usedto send an RS and four symbols are used to send ACK/NACK information inone slot of a subframe of an extended CP, for example, if six CSs can beused in the frequency domain and two orthogonal cover (OC) resources canbe used in the time domain, HARQ acknowledgement from a total of 12different UEs may be multiplexed within one PUCCH RB.

The PUCCH format 1 is described below. A scheduling request (SR) istransmitted in such a manner that a UE requests scheduling or does notscheduling. An SR channel reuses the ACK/NACK channel structure in thePUCCH formats 1a/1b and is configured according to an on-off keying(OOK) method based on the ACK/NACK channel design. A reference signal isnot transmitted in the SR channel. Accordingly, a sequence of a length 7is used in the case of a common CP, and a sequence of a length 6 is usedin the case of an extended CP. Different cyclic shifts or orthogonalcovers may be allocated to an SR and ACK/NACK. That is, for positive SRtransmission, a UE transmits HARQ ACK/NACK through resources allocatedfor the SR. For negative SR transmission, a UE transmits HARQ ACK/NACKthrough resources allocated for ACK/NACK.

An enhanced-PUCCH (e-PUCCH) format is described below. The e-PUCCH maycorrespond to the PUCCH format 3 of the LTE-A system. A block spreadingscheme may be applied to ACK/NACK transmission using the PUCCH format 3.

The block spreading scheme is a method of modulating the transmission ofa control signal using the SC-FDMA method unlike the existing PUCCHformat 1 series or 2 series. As shown in FIG. 8, a symbol sequence maybe spread on the time domain using orthogonal cover code (OCC) andtransmitted. The control signals of a plurality of UEs may bemultiplexed on the same RB using the OCC. In the case of theaforementioned PUCCH format 2, one symbol sequence is transmitted in thetime domain and the control signals of a plurality of UEs aremultiplexed using the cyclic shift (CS) of a CAZAC sequence. Incontrast, in the case of a block spreading-based PUCCH format (e.g., thePUCCH format 3), one symbol sequence is transmitted in the frequencydomain and the control signals of a plurality of UEs are multiplexedusing time domain spreading using the OCC.

HARQ Process in LTE/LTE-A System

In the current LTE, 8 HARQ process is used for withdrawing error ofdata, and two types of HARQ are defined according to retransmissiontiming of data as follows.

FIG. 16 illustrates an example of asynchronous HARQ operation indownlink.

Referring to FIG. 16, when transmitting retransmission data, an eNB thatreceives NACK transmits the data by setting NDI in a DL grant (DCIformat 1) as a bit that represents a retransmission. In this case, theNDI includes HARQ process ID, and represents which data isretransmitted.

FIG. 17 illustrates an example of synchronous HARQ operation indownlink.

Referring to FIG. 17, an eNB that transmits NACK transmitsretransmission data with the same resource as an initial datatransmission by allocating data resource for retransmission to a newresource by setting NDI in a DL grant (DCI format 1) as a bit thatrepresents a retransmission, or omitting a UL grant. In this case, theretransmission timing is always fixed at the subframe after 4 ms whenreceiving NACK.

The HARQ scheme tries to correct error for a received code basically,and determines whether to retransmit it by using simple error detectioncode such as Cyclic Redundancy Check (CRC). For a retransmission, theHARQ scheme is divided into three types as follows, and LTE performs theHARQ scheme through CC (second technique) or IR (third technique).

1) Type-I HARQ Scheme: A receiver discards a packet having an error andrequests for retransmission, and a transmitter transmits the packetwhich is the same as that of an initial transmission. By discarding apacket having an error, an increase in reliability of a system and aperformance increase through FEC are obtained.

2) Type-I HARQ Scheme with Chase Combining: This is a technique, insteadof discarding a packet having an error, of using the packet by combiningit with a retransmitted packet. By combining several packets, an effectof increasing signal power may be obtained, consequently.

3) Type-II HARQ Scheme (Incremental redundancy Scheme): This is atechnique of using a code of high code rate in an initial transmissionand transmitting an additional redundancy when a retransmission occursin order to prevent the case of transmitting a code of high redundancyin an initial transmission unnecessarily in the case of Type-I.

PHICH (Physical HARQ Indication Channel)

A PHICH is described below.

In the LTE system, since SU-MIMO is not supported in uplink, one PHICHtransmits only the PUSCH of one UE, that is, 1-bit ACK/NACK for a singlestream.

The 1-bit ACK/NACK is coded into three bits using a repetition codewhose code rate is 1/3. Three modulation symbols are generated bymodulating the coded ACK/NACK according to a binary phase key-shifting(BPSK) method. The modulation symbol is spread using a spreading factor(SF)=4 in a normal CP structure and using SF=2 in an extended CPstructure.

When the modulation symbols are spread, an orthogonal sequence is used.The number of orthogonal sequences used becomes SF*2 in order to applyI/O multiplexing.

PHICHs spread using the SF*2 orthogonal sequence may be defined as onePHICH group. Layer mapping is performed on the spread symbols. Thelayer-mapped symbols are subjected to resource mapping and transmitted.

A PHICH transmits HARQ ACK/NACK according to PUSCH transmission. Aplurality of PHICHs mapped to the resource elements of the same setforms a PHICH group. The PHICHs within the PHICH group are distinguishedby different orthogonal sequences. In the FDD system, n_(PHICH) ^(group)that is the number of PHICH groups is constant in all of subframes, andmay be determined by Equation 1.

$\begin{matrix}{N_{PHICH}^{group} = \left\{ \begin{matrix}{\left\lceil {N_{g}\left( {N_{RB}^{DL}/8} \right)} \right\rceil,} & {{for}\mspace{14mu}{normal}\mspace{14mu}{cyclic}\mspace{14mu}{prefix}} \\{{2 \times \left\lceil {N_{g}\left( {N_{RB}^{DL}/8} \right)} \right\rceil},} & {{for}\mspace{14mu}{extended}\mspace{14mu}{cyclic}\mspace{14mu}{prefix}}\end{matrix} \right.} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In Equation 1, Ng is transmitted in a higher layer through a physicalbroadcast channel (PBCH), and Ng∈{1/6, 1/2, 1, 2}. The PBCH carriessystem information that is essential for a UE to communicate with aneNB. System information transmitted through the PBCH is called a masterinformation block (MIB).

In contrast, system information transmitted through a physical downlinkcontrol channel (PDCCH) is called a system information block (SIB).N_(RB) ^(DL) is a downlink bandwidth configuration expressed by amultiplication of N_(SC) ^(RB), that is, the size of a resource block inthe frequency domain. A PHICH group index n_(PHICH) ^(group) is any oneinteger of 0 to n_(PHICH) ^(group)−1.

Resources used for a PHICH may be determined based on the smallest PRBindex when the resources of a PUSCH are allocated and the cyclic shiftvalue of a demodulation reference signal (DMRS) transmitted in an uplink(UL) grant.

Resources to which a PHICH is mapped (hereinafter referred to as “PHICHresources”) may be expressed as (n_(PHICH) ^(group), n_(PHICH) ^(seq)),that is, an index pair. n_(PHICH) ^(group) indicates a PHICH groupindex, and n_(PHICH) ^(seq) indicates an orthogonal sequence indexwithin the PHICH group. The (n_(PHICH) ^(group), n_(PHICH) ^(seq)) maybe determined by Equation 2 below.n _(PHICH) ^(group)=(I _(PRB) _(RA) +n _(DMRS))mod N _(PHICH) ^(group)+I _(PHICH) N _(PHICH) ^(group) , n _(PHICH) ^(seq)=(└I _(PRB_RA) /N_(PHICH) ^(group) ┘+n _(DMRS))mod 2N _(SF) ^(PHICH)  [Equation 2]

In Equation 2, the nDMRS is mapped from a cyclic shift for ademodulation reference signal (DMRS) field in the most recent PDCCHhaving an uplink DCI format for a transport block, which is related tothe transmission of a corresponding PUSCH.

In contrast, if a PDCCH having an uplink DCI format for the sametransport block is not present, an initial PUSCH for the same transportblock is scheduled semi-persistently or when the initial PUSCH isscheduled by a random access response approval signal, the nDMRS is setto 0.

N_(SF) ^(PHICH) indicates a spreading factor size used for PHICHmodulation.

I_(PRB_RA) is the same as I_(PRB_RA) ^(lowest_index) if it is the firsttransport block of a PUSCH related to a PDCCH or if the number oftransport blocks manually recognized when a related PDCCH is not presentis not the same as the number of transport blocks indicated in the mostrecent PDCCH related to the corresponding PUSCH.

In contrast, if it is the second transport block of a PUSCH related tothe PDCCH, it is the same as I_(PRB_RA) ^(lowest_index)+1. In this caseI_(PRB_RA) ^(lowest_index) corresponds to the lowest PRB index of thefirst slot of the transmission of the corresponding PUSCH.

n_(PHICH) ^(group) indicates the number of PHICH groups configured by ahigher layer.

I_(PHICH) has “1” if a PUSCH is transmitted in a subframe index 4 or 9and “0” if not in the uplink-downlink configuration 0 of a TDD system.

Table 5 shows a mapping relation between a cyclic shift for a DMRS fieldused to determine PHICH resources in a PDCCH having an uplink DCI formatand an nDMRS.

TABLE 5 Cyclic Shift for DMRS Field in PDCCH with uplink DCI formatnDMRS 000 0 001 1 010 2 011 3 100 4 101 5 110 6 111 7

DCI Format 0 (UL Grant) in LTE/LTE-A System

FIG. 18 is a diagram illustrating an example of DCI format 0.

In LTE a PUSCH resource is allocated through a UL grant of an eNB.

By transmitting DCI format 0 CRC masked by C-RNTI of a UE through aPDCCH, the LTE UL grant makes a UE to generate uplink data and transmitit according to an instruction of an eNB through receiving thecorresponding information.

That is, FIG. 18 and Table 6 represent parameters of DCI format 0.

TABLE 6 Format 0(release 8) Format 0(release 8) Carrier Indicator Flagfor format 1A differentiation Flag for format 0/format 1Adifferentiation Hopping flag Hopping flag Resource block assignment(RIV)Resource block assignment(RIV) MCS and RV MCS and RV NDI(New DataIndicator) NDI(New Data Indicator) TPC for PUSCH TPC for PUSCH CyclicShift for DM RS Cyclic Shift for DM RS UL index(TDD only) UL index(TDDonly) Downlink Assignment Index(DAI) Downlink Assignment Index(DAI) CQIrequest(1 bit) CSI request(1 or 2 bits: 2 bits are multi carrier) SRSrequest Resource allocation type

Herein, the lengths of Hopping flag and RIV may have different lengthsaccording to a system bandwidth as follows.

Hopping flag

: 1 (1.4/3/5 Mhz) or 2 (10/15/20 Mhz) bits

Resource Block Assignment

: 5 (1.4 Mhz), 7 (3/5 Mhz), 11 (10 Mhz), 12 (15 Mhz), 13 (20 Mhz) bits

A UL data transmission method in LTE (-A) or 802.16m is brieflydescribed.

The cellular system such as LTE (-A) or 802.16m uses a resourceallocation scheme based on an eNB scheduling.

In the system that uses the resource allocation scheme based on an eNBscheduling as such, a UE that has data to transmit (i.e., UL data)requests a resource for transmitting the corresponding data to an eNBbefore transmitting the data.

The scheduling request of a UE may be performed through a SchedulingRequest (SR) transmission to a PUCCH or a Buffer Status Report (BSR)transmission to a PUSCH.

In addition, in the case that a resource for transmitting the SR or theBSR is not allocated to a UE, the UE may request an uplink resource toan eNB through the RACH procedure.

As such, an eNB that receives the scheduling request from a UE allocatesthe uplink resource that the corresponding UE is going to use to the UEthrough a downlink control channel (i.e., UL grant message, DCI in thecase of LTE (-A)).

In this case, the UL grant transmitted to the UE may indicate whichsubframe the resource that is allocated to the UE corresponds to byexplicit signaling, but may also define an appointed time between the UEand the eNB using the resource allocation for the subframe after aspecific time (e.g., 4 ms in the case of LTE).

As such, the case that an eNB allocates a resource after X ms (e.g., 4ms in the case of LTE) to a UE means that the eNB allocates the resourceof UE by considering all of the times for receiving and decoding a ULgrant and for preparing and encoding the data to transmit.

DCI Format 3/3A in LTE/LTE-A System

In the case of LTE(-A), DCI format 3/3A may be used for a power controlof a PUCCH or a PUSCH.

DCI format 3/3A may be constructed by N TPC commands as represented inTable 7 or Table 8 below.

Here, N may be preconfigured to a UE through an RRC message. Such DCIformat 3/3A may transmit information of 2N/N bits length, and istransmitted through a common search space by being CRC masked withTPC-RNTI.

A UE performs a power control for transmitting data to a PUCCH or aPUSCH by receiving a TPC command that corresponds to its own location.

TABLE 7 Format 3(release 8) - TPC-RNTI Field Name Length(Bits) CommentTPC command 2 number 1 TPC command 2 number 2 TPC command 2 number 3 . .. TPC command 2 The size of N is dependent number N on the payload sizeof DCI format 0 for the system BW

TABLE 8 Format 3A(release 8) - TPC-RNTI Field Name Length(Bits) CommentTPC command 1 number 1 TPC command 1 number 2 TPC command 1 number 3 . .. TPC command 1 The size of N is dependent number N on the payload sizeof DCI format 0 for the system BW

Hereinafter, a procedure for an eNB to send down a PDCCH to a UE will bedescribed.

FIG. 19 is a block diagram illustrating a structure of a PDCCH.

A BS determines a PDCCH format according to DCI to be transmitted to aUE, attaches a CRC to control information, and masks a unique identifier(referred to as a radio network temporary identifier (RNTI)) to the CRCaccording to an owner or usage of the PDCCH (block 1910).

In the case that the PDCCH is for a specific wireless device, a uniqueidentifier (e.g., cell-RNTI (C-RNTI)) of the UE may be masked to theCRC.

Alternatively, in the case that the PDCCH is for a paging message, apaging indication identifier (e.g., paging-RNTI (P-RNTI)) may be maskedto the CRC.

In the case that the PDCCH is for system information, a systeminformation identifier (e.g., system information-RNTI (SI-RNTI)) may bemasked to the CRC. In order to indicate a random access response that isa response for transmission of a random access preamble of the UE, arandom access-RNTI (RA-RNTI) may be masked to the CRC. In order toindicate a transmit power control (TPC) command for a plurality ofwireless devices, a TPC-RNTI may be masked to the CRC.

When the C-RNTI is used, the PDCCH carries control information for aspecific wireless device (such information is called UE-specific controlinformation), and when other RNTIs are used, the PDCCH carries commoncontrol information received by all or a plurality of wireless devicesin a cell.

The CRC-attached DCI is encoded to generate coded data (block 1920).

Encoding includes channel encoding and rate matching.

The encoded data is modulated to generate modulation symbols (block1930).

The modulation symbols are mapped to physical resource elements (REs)(block 1940). The modulation symbols are respectively mapped to the REs.

FIG. 20 illustrates an example of resource mapping of a PDCCH.

Referring to FIG. 20, R0 denotes a reference signal of a 1st antenna, R1denotes a reference signal of a 2nd antenna, R2 denotes a referencesignal of a 3rd antenna, and R3 denotes a reference signal of a 4thantenna.

A control region in a subframe includes a plurality of control channelelements (CCEs). The CCE is a logical allocation unit used to providethe PDCCH with a coding rate depending on a state of a radio channel,and corresponds to a plurality of resource element groups (REGs). TheREG includes a plurality of resource elements (REs). According to therelationship between the number of CCEs and the coding rate provided bythe CCEs, a PDCCH format and a possible PDCCH bit number are determined.

One REG (indicated by a quadruplet in the drawing) includes 4 REs. OneCCE includes 9 REGs.

The number of CCEs used to configure one PDCCH may be selected from {1,2, 4, 8}. Each element of {1, 2, 4, 8} is referred to as a CCEaggregation level.

A control channel including one or more CCEs performs interleaving inunit of REG, and is mapped to a physical resource after performingcyclic shift based on a cell identifier (ID).

FIG. 21 illustrates an example of distributing CCEs across a systemband.

Referring to FIG. 21, a plurality of logically contiguous CCEs is inputto an interleaver. The interleaver permutes the sequence of theplurality of input CCEs on an REG basis.

Accordingly, the time/frequency resources of one CCE are physicallydistributed to a total time/frequency area in the control region of asubframe. As a consequence, while the control channel is configured on aCCE basis, it is interleaved on an REG basis, thereby maximizingfrequency diversity and an interference randomization gain.

FIG. 22 illustrates an example of PDCCH monitoring.

In 3GPP LTE, blind decoding is used to detect a PDCCH. Blind decoding isa process of de-masking a cyclic redundancy check (CRC) of a receivedPDCCH (PDCCH candidate) with a desired identifier to check a CRC error,thereby allowing a UE to identify whether the PDCCH is a control channelof the UE. A UE does not recognize a position in which a PDCCH thereofis transmitted in a control region and a CCE aggregation level or DCIformat used to transmit the PDCCH.

A plurality of PDCCHs may be transmitted in one subframe. A UE monitorsa plurality of PDCCHs in each subframe.

Here, the monitoring refers to an attempt of a UE to decode a PDCCHaccording to a monitored PDCCH format.

In 3GPP LTE, a search space is used to reduce load caused by blinddecoding. A search space may denote a monitoring set of CCEs for aPDCCH. A UE monitors a PDCCH in a corresponding search space.

A search space is divided into a common search space and a UE-specificsearch space. The common search space is a space for searching for aPDCCH having common control information, which includes 16 CCEs with CCEindexes of 0 to 15 and supports a PDCCH having a CCE aggregation levelof {4, 8}. However, a PDCCH (DCI format 0 and 1A) carrying UE-specificinformation may also be transmitted to the common search space. TheUE-specific search space supports a PDCCH having a CCE aggregation levelof {1, 2, 4, 8}.

TABLE 9 Number of Search Space Aggregation Size PDCCH Type Level(L) (inCCEs) candidates DCI formats UE-Specific 1 6 6 0, 1, 1A, 1B, 2 12 6 1C,2, 2A 4 8 2 8 16 2 Common 4 16 4 0, 1A, 1C, 3/3A 8 6 2

A size of a search space is determined by Table 9 above, and a differentstart point of a search space is defined for a common search space and aUE-specific search space. A start point of a common search space isfixed regardless of subframes, while a start point of a UE-specificsearch space may change by subframe according to an UE ID (e.g.,C-RNTI), a CCE aggregation level and/or a slot number in a radio frame.When the start point of the UE-specific search space is in the commonsearch space, the UE-specific search space and the common search spacemay overlap.

In an aggregation level of L∈{1, 2, 4, 8}, a search space S^((L)) _(k)is defined as an aggregation of PDCCH candidates. A CCE that correspondsto PDCCH candidate m of a search space S^((L)) _(k) is given as below.

$\begin{matrix}{{L \cdot \left\{ {\left( {Y_{k} + m} \right){mod}\left\lfloor \frac{N_{{CCE},k}}{L} \right\rfloor} \right\}} + i} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack\end{matrix}$

Here, i=0, 1, . . . , L−1, m=0, . . . , M^((L))−1, N_(CCE,k) are totalnumber of a CCE that may be used for a transmission of a PDCCH in acontrol region of subframe k.

A control region includes an aggregation of CCEs numbered from 0 toN_(CCE,k)−1. M^((L)) is the number of PDCCH candidates in CCEaggregation level L in a given search space. In a common search space,Y_(k) is set to 0 with respect to two aggregation levels, L=4 and L=8.In a UE-specific search space of aggregation level L, variable Y_(k) isdefined as below.Y _(k)=(A·Y _(k−1))mod D  [Equation 5]

Here, Y⁻¹ _(=n) _(RNTI)≠0, A=39827, D=65537, k=floor(n_(s)/2) and n_(s)are slot number in a radio frame.

FIG. 23 is a diagram illustrating an example of a logical channelprioritization in the LTE system.

First, data transmitted and received between a UE and an eNB maygenerate different Data Radio Bearer (DRB) with each other according toa service property, and each DRB may be mapped to a specific DedicatedTraffic Channel (DTCH).

Here, the DRB of LTE may be generated up to maximum 32, and accordingly,DRB IDs may be allocated with values from 1 to 32.

In addition, the DRB transmitted to a DTCH may be mapped to logicalchannel IDs (LCIDs) from 3 to 10, and a DRB ID may be mapped to an LCIDfor a DTCH.

Furthermore, maximum 8 DTCHs that may be generated in LTE may be mappedto a logical channel group (LCG) depending on a service type of a DRB,and this means that an LCID for one or more DTCHs may be mapped to anLCG ID.

Here, an LCG ID is a unit that a UE reports a Buffer Status to an eNB.

The data transmitted to a DTCH logical channel is mapped to a downlinkshare channel (DL-SCH) or an uplink share channel (UL-SCH) of a MAClayer, and this is transmitted by being mapped to a PDSCH or a PUSCH ofa PHY layer, respectively.

In this case, a MAC layer may transmit the data generated from differentDTCH logical channel that may be transmitted and received to a specificUE by multiplexing it with a single physical resource.

According to it, multiplexed data are constructed as a single transportblock and transmitted in the same resource, and the same HARQ process isperformed.

LTE provides the logical channel prioritization function that a UE maytransmit data having high priority more quickly by providing a priorityfor a logical channel with respect to an UL data of the UE.

This set a Prioritized Bit Rate (PBR) for each logical channel in orderto prevent the starvation phenomenon of data transmitted from a logicalchannel of which priority is low, and accordingly, data of whichpriority is high can be transmitted using a resource of higher ratio.

As shown in FIG. 23, data of a specific DRB is mapped to a singlelogical channel, and has a PRB according to the priority. After data asmuch as the PRB which is set is allocated to a resource according to thepriority, the data is transmitted by applying all of the allocatedresources.

In this case, the data generated from an SRB may have a PRB infinityvalue, and this is designed for transmitting all of the data that areintended to be transmitted at a time by using the allocated resources.

CRC Calculation in LTE/LTE-A

Currently, in LTE(-A), as a method for detecting an error of data, CRCis attached to a transport block and transmitted.

It is defined that 16-bit CRC is used by using an RNTI identifier forerror detection in a PDCCH and 24-bit CRC is used for a datatransmission.

More specifically, it is defined that CRC of CRC24A type is used for TBCRC and CRC of CRC24B type is used for code block CRC.

FIG. 24 illustrates an example of a signal processing procedure of a ULshared channel which is a transport channel in a wireless communicationsystem to which the present invention may be applied.

Hereinafter, the signal processing procedure of the UL shared channel(hereinafter, “UL-SCH”) may be applied to one or more transport channelsor control channel types.

Referring to FIG. 24, a UL-SCH forwards data to a coding unit in a formof Transport Block (TB) once in every transmission time interval (TTI).

CRC parity bits p₀, p₁, p₂, p₃, . . . , p_(L−1) are attached to bits a₀,a₁, a₂, a₃, . . . , a_(A−1) of a transport block forwarded from a higherlayer (step, S120). In this case, A is the size of the transport blockand L is the number of parity bits.

The parity bits are generated by one of the following cyclic generatorpolynomials.

-   -   gCRC24A(D)=[D24+D23+D18+D17+D14+D11+D10+D7+D6+D5+D4+D3+D+1] and;    -   gCRC24B(D)=[D24+D23+D6+D5+D+1] for a CRC length L=24 and;    -   gCRC16(D)=[D16+D12+D5+1] for a CRC length L=16.    -   gCRC8(D)=[D8+D7+D4+D3+D+1] for a CRC length ofL=8.

The input bit to which CRC is attached is as represented as b₀, b₁, b₂,b₃, . . . , b_(B−1). In this case, B represents a bit number of atransport block including CRC.

b₀, b₁, b₂, b₃, . . . , b_(B−1) is segmented into several code blocks(CB) depending on a TB size, and CRC is attached to the segmentedseveral CBs (step, S121).

After the code block segmentation and CRC attachment, a bit is asrepresented as c_(r0), c_(r1), c_(r2), c_(r3), . . . , c_(r(K) _(r) ⁻¹⁾.Herein, r is the number (r=0, . . . , C−1) of a code block, and K, is abit number according to r.

Subsequently, channel coding is performed (step, S122). A output bitafter the channel coding is as represented as d_(r0) ^((i)), d_(r1)^((i)), d_(r2) ^((i)), d_(r3) ^((i)), . . . , d_(r(D) _(r) ⁻¹⁾ ^((i)).In this case, i is a stream index which is coded, and may have a valueof 0, 1 or 2. D_(r) represents a bit number of i^(th) coded stream forcode block r. r is the number (r=0, . . . , C−1) of a code block, and Crepresents total number of code blocks. Each code block may be coded byturbo coding, respectively.

Subsequently, rate matching is performed (step, S123). After goingthrough the rate matching, the bit is as represented as e_(r0), e_(r1),e_(r2), e_(r3), . . . , e_(r(E) _(r) ⁻¹⁾. In this case, r is the number(r=0, . . . , C−1) of a code block, and C represents total number ofcode blocks. E_(r) represents the number of bits which are rate matchingof r^(th) code block.

Subsequently, a concatenation between code blocks is performed again(step, S124). After the concatenation of performed, the bit is asrepresented as f₀, f₁, f₂, f₃, . . . , f_(G−1). In this case, Grepresents total number of coded bits for a transmission. When controlinformation is multiplexed with a UL-SCH transmission, the bit numberused for control information transmission is not included.

Meanwhile, when control information is transmitted in a PUSCH, channelcoding is independently performed for each of CQI/PMI, RI, ACK/NACK thatare control information (steps, S126, S127 and S128). Since differentcoded symbols are allocated for each type of the control information,each of the types of the control information has different coding rates.

In Time Division Duplex (TDD), two types of modes, ACK/NACK bundling andACK/NACK multiplexing, are supported by higher layer configuration asACK/NACK feedback mode. For the ACK/NACK bundling, ACK/NACK informationbit is configured by 1 bit or 2 bits, and for the ACK/NACK multiplexing,ACK/NACK information bit is configured by 1 bit to 4 bits.

In step S124, after the step of concatenation between code blocks,multiplexing of the coded bits f₀, f₁, f₂, f₃, . . . f_(G−1) of UL-SCHdata and the coded bits q₀, q₁, q₂, q₃, . . . , q_(N) _(L) _(·Q) _(CQI)⁻¹ of CQI/PMI is performed (step, S125). A result of multiplexing ofdata and CQI/PMI is as represented as g₀, g₁, g₂, g₃, . . . , g_(H′−1).In this case, g_(i)(i=0, . . . , H′−1) represents a column vector havinga length of (Q_(m)·N_(L)). Herein, H=(G+N_(L)·Q_(CQI)) andH′=H/(Q_(m)·N_(L)). N_(L) represent the number of layer in which aUL-SCH transport block is mapped, and H represents the number of totalcoded bits which is allocated for UL-SCH data and the CQI/PMIinformation to N_(L) transport layers to which a transport block ismapped.

Subsequently, the multiplexed data, CQI/PIM, separately channel coded RIand ACK/NACK are channel-interleaved, and an output signal is generated(step, S129).

As shown in FIG. 24, TB of a predetermined length or longer may besegmented, and the segmented block is called a code block. That is, TBof a predetermined length or shorter is transmitted in which only TB CRC(CRC24A) is attached, but in the TB of a predetermined length or longer,TB to which TB CRC (CRC24B) is attached is segmented again, andtransmitted by attaching code block CRC (CRC24B) to each code block.

FIG. 25 is a diagram illustrating a time until a UE transmits actualdata through 5 step scheduling request procedure using PUCCH SRresource.

As shown in FIG. 25, a UE may transmit actual uplink data after about 17ms from the time of transmitting an SR signal.

In this case, the SR resource allocated to the UE may be allocated to aPUCCH with a specific period, minimum 1 ms to maximum 80 ms.

Here, in the case that the SR of 1 ms period is allocated to thecorresponding UE, an average time for the UE to wait for the PUCCHresource for an SR transmission is 0.5 ms, and the delay time until thedata transmission through a scheduling request to an eNB takes 17.5 ms.

In the case that a UE has an uplink resource allocated from an eNBbeforehand, the UE may transmit the resource request for newly generateddata by using the resource allocated beforehand.

Alternately, the UE may request an additional resource by transmitting aBSR together with the data transmitted with the resource allocatedbeforehand.

In this case, as shown in FIG. 26, the delay of 9 ms occurs untiltransmitting uplink data after a UE request a BSR.

In the case that there is no PUCCH SR resource or PUSCH resource thatthe UE is allocated from the eNB or the uplink is not synchronized, theUE may request the resource for the newly generated data using the RACHprocedure.

That is, as shown in FIG. 27, the delay of 17 ms occurs until the UEtransmits uplink data from the time of transmitting the RACH preamble tothe eNB.

In this case, the PRACH resource that is available to transmit the RACHpreamble may be configured with a specific period for each cell.Assuming the PRACH resource has the period of minimum 1 ms, the datatransmission delay of average 17.5 ms may occur.

As described in FIG. 25 to FIG. 27, the UE may transmit actual data byundergoing the delay of minimum 9 ms to maximum 17.5 ms for transmittinguplink data.

Accordingly, the eNB allocates an optimal resource to each UE in achannel environment, and accordingly, the resource efficiency may bemaximized, but the transmission delay occurs.

The requirement of 5G is increasing for supporting various real timeapplication services such as health care, traffic safety, disastersafety, remote medical control, and so on.

Accordingly, 5G sets it as a goal to construct an ultra low latencysystem that has an extremely short response time to the extent that auser is unable to notice even in the case that the tactility informationwhich is mostly sensitive to the delay time among five senses of a humanis provided through an internet (target delay: E2E or Radio 1 ms).

Delay of a data transmission is needed to be minimized in order toprovide such a 5G communication service, but a data transmission of acurrent system is designed to cause delay additionally as below.

Downlink Data Transmission Delay

-   -   Connected UE: 0 ms (no delay)    -   Dormant UE: Average 1 ms to 280 ms delay occurs depending on DRX        cycle set to a UE (short DRX cycle: 2˜640 ms, long DRX cycle:        10˜2560 ms).    -   Idle UE: Average 160 ms, 280 ms+initial access delay occurs        depending on paging DRX cycle set to a UE (paging cycle:        320˜2560 ms, initial access: 50 ms˜100 ms (LTE-A: 50 ms/LTE: 100        ms)).

Uplink Data Transmission Delay

-   -   Synchronized & dormant UE: 17.5 ms delay occurs (5-step SR).    -   Unsynchronized UE: 17.5 ms delay occurs (SR through RACH).    -   Connected UE to which uplink resource is allocated: 9 ms (Data        is transmitted through BRS transmission)

As such, various time delays may occur in transmission/reception of datafor a UE depending on the state of UE, and particularly, delay ofdownlink data reception may occur with various lengths for a UE in adormant or idle state.

However, this is one of methods for decreasing power consumption of aUE, and it is required to examine closely a relationship between datareception delay and power consumption.

However, for the data transmission delay in an uplink data transmission,it is identified that additional delay is bound to occur since a UE usesthe data transmission scheme based on an eNB scheduling although the UEis able to transmit data whenever it is required.

A service which may prevent a secondary accident or respond an emergencysituation rapidly is expected to be provided as a main low latencyservice of future 5G communication, by quickly notifying information ofan accident or state that may occur due to a specific event on anunpredictable time from a various end users such as a human, a machine(vehicle or sensor), or the like to an eNB or a neighboring UE/user.

Such a low latency service makes it possible to perform a subsequentprocedure by transmitting mainly uplink data quickly.

Owing to this, a fast transmission of unlink data which is an initiationstep of a corresponding service s one of important factors thatinfluences overall service delay.

Due to the reasons above, in order to support a low latency service of anew 5G communication, it is considered that delay in an uplink datatransmission is a factor that should be decreased necessarily.

Hereinafter, a fast UL data transmission method proposed in the presentdisclosure will be described, which is to support a low latency servicein a wireless communication system such as 5G.

Particularly, as shown in FIG. 28, the present disclosure provides amethod for transmitting a new UL data such as urgent data quickly byusing a retransmission resource that a UE is allocated with in advance.

In the case that a UE transmits UL data to an eNB using a retransmissionresource, the present disclosure provides a method for transmitting anindicator indicating whether the UL data is retransmission data or newdata together.

The indicator may be represented as a New Data Indicator (NDI) field (orinformation), and hereinafter, the indicator is represented as ‘NDI’,‘NU field’ or ‘NDI information’.

FIG. 28 is a diagram illustrating an example of a method fortransmitting UL data quickly by using a retransmission resource proposedin the present disclosure.

Referring to FIG. 28, when an urgent event occurs in N=10 subframe (SF)of (step, S2810), a UE may preempt a retransmission resource in N=12 SF(with respect to initial UL data transmitted in N=4 SF) and may transmitNDI information in relation to PHY layer and urgent data togetherthrough the preempted retransmission resource (step, S2820).

A method proposed in the present disclosure may have the configurationas represented in 1 to 3 below.

The configuration (NDI transmission on a PUSCH and NDI transmission on aPUCCH) of 1 and 2 below defines NDI, and represents a method fortransmitting it. And the configuration of 3 below represents anoperation method of a UE and an eNB in relation to NDItransmission/reception.

1. New Data Indicator (NDI) Transmission on a PUSCH

(1) NDI transmission method through a PHY header definition

(2) NDI transmission method using a new CRC type

(3) NDI transmission method using UL-SCH data and multiplexing of NDIsignaling in a PUSCH resource

3. Operational Procedure of a UE and an eNB

(1) The case that HARQ is not performed for urgent data or preemptiondata

(2) The case that HARQ is performed for urgent data or preemption data

That is, in the case that a specific UE (e.g., urgent UE, etc.) isrequired to transmit urgent data using the configuration of 1 to 3above, a method proposed in the present disclosure provides a method fortransmitting urgent data quickly to an eNB using the resource (e.g.,retransmission resource) allocated in advance to the UE itself.

In the existing case, in order to prevent starvation phenomenon of dataof which priority is low, a UE distributes an amount of data withdifferent ratio (Prioritized Bit Rate; PBR) according to priorities ofdata (DRB or logical channel) arrived in a buffer for a resourceallocated to the UE itself, and transmits it to an eNB aftermultiplexing it in the same PHY resource.

That is, FIG. 28 is a diagram illustrating a resource preemptionprocedure for an initial data transmission.

As shown in FIG. 28, in the case that an urgent event occurs after a UEreceives a UL grant for an initial data transmission from an eNB, the UEtransmits urgent data preferentially using a resource allocated throughthe received UL grant than data of which priority is low.

However, as shown in FIG. 28, in the case that a UE receives a UL grantfrom an eNB, urgent data arrives at a buffer after the UE transmitsinitial data to the eNB, and the UE is allocated with a retransmissionresource for performing HARQ from the eNB owing to a failure of theinitial data transmission, although the UE is allocated with theretransmission resource, the UE is unable to transmit the urgent datausing the allocated retransmission resource.

The reason is because the exiting HARQ technique is designed to obtain acoding gain by transmitting combined bits as the same as data used in aninitial transmission (or different redundancy version of the samecombined bits).

Accordingly, in the UL HARQ process using synchronous HARQ, it isimpossible to transmit the combined bits for different data as aretransmission resource for a specific HARQ process.

When a UE receives NACK from an eNB for data transmitted to the eNB, thecurrent LTE(-A) defines that the UE may perform a retransmission forinitial data to the eNB in the SF after 8 ms and after transmitting theinitial data.

That is, the synchronous HARQ process is a method of using eight HARQprocesses with being synchronized with ACK/NACK without HARQ process ID(PID) signaling.

Accordingly, in the synchronous HARQ process, a retransmission may beperformed by using the resource allocated for an initial datatransmission without any change (Non-adaptive HARQ) or being newlyallocated (Adaptive HARQ) with a UL grant together with receiving NACK.

FIG. 29 is a diagram illustrating a problem that may occur in a methodfor transmitting urgent data by preempting a retransmission resource.

As shown in FIG. 29, when a UE transmit urgent data to an eNB through aretransmission resource in N=12 SF (step, S2910), the eNB performs HARQcombining of different data, and is unable to receive data transmittedby the UE (step, S2920).

That is, HARQ error occurs for HARQ process ID 0 in relation to aninitial data transmission of a UE.

In a future 5G technique, owing to an advent of a new low latencyservice, needs for transmitting urgent data are increasing.

Therefore, according to a method for transmitting new data using aresource allocated for a retransmission proposed in the presentdisclosure, data of a UE may be transmitted quickly to an eNB, andconsequently, delay of data transmission may be decreased.

That is, as shown in FIG. 29 described above, in the case that an urgentevent (or urgent data) occurs after a UE receives a transmission failureindicator (HARQ NACK) from an eNB, the present disclosure provides amethod for defining a new data indicator that enables the UE to be ableto transmit urgent data, and the like by using the resource allocatedfor a retransmission.

A UE transmits an indicator for transmitting new data together with newdata, not retransmitting a previous data using a resource which isalready allocated from an eNB.

Accordingly, an eNB that receives new data with the indicator does notperform HARQ combining the new data with the data stored in a HARQbuffer such that a UE may transmit UL data quickly using aretransmission resource.

Hereinafter, among the configurations proposed in the presentdisclosure, a method for transmitting a New Data Indicator (NDI) on aPUSCH and the related procedure of a UE and an eNB will be described indetail with reference to drawings.

First, a method for transmitting NDI information on a PUSCH is describedfor transmitting urgent data using a retransmission resource.

1. New Data Indicator(NDI) on the PUSCH

This method represents a method for New Data Indicator (NDI) informationindicating whether the data transmitted on the PUSCH is a retransmissiondata (for previous data) or a new data like an urgent data, and the liketo be transmitted together with UL data in a PUSCH resource.

The ‘previous data’ used in the present disclosure is a term used forthe convenience for distinguishing it from ‘new data’ like urgent data,and the like, and may mean UL data or initial UL data that a UEtransmits to an eNB before an urgent event occurs.

This method may include (1) a method for transmitting NDI informationthrough PHY header definition, (2) a method for transmitting NDIinformation using a new CRC type and (3) a method for transmitting NDIinformation using UL-SCH data in a PUSCH resource and multiplexing ofNDI signaling.

(1) First Embodiment: A Method for Transmitting NDI Through PHY HeaderDefinition

A first embodiment represents a method for newly defining PHY headerincluding NDI information and transmitting it together with UL data of aUE.

FIG. 30 is a diagram illustrating an example of a MAC PDU formatincluding PHY header proposed in the present disclosure.

The PHY header 3010 is preferred to be located in forefront of MAC PDU3000.

In addition, the information(s) included in the PHY header is defined asthe information to be forwarded to a PHY layer again after performingTransport Block CRC check and decoding on it.

As shown in FIG. 30, a MAC PDU includes a MAC header 3020, a MAC SDU3030 and the newly defined PHY header 3010.

The MAC PDU may be mapped to a specific physical resource together witha CRC.

In addition, the PHY header includes at least one of a PHY headerIndicator (PHI) field 3011 or a New Data Indicator (NDI) field 3012.

The PHI indicates an indicator representing whether the NDI field isincluded in a MAC PDU (or an indicator representing whether the NDIfield is transmitted with a MAC PDU or not).

As an example, in the case that a value of the PHY header indicator isset to ‘0’, a MAC PDU may represent that it does not include the NDIfield or a MAC header is located just behind the PHY header indicatorfield.

In the case that a value of the PHY header indicator is set to ‘1’, aMAC PDU may represent that it includes the NDI field or the NDI field isadded after the PHY header indicator field (refer to FIG. 30).

The PHY header indicator field may be used for minimizing signalingoverhead owing to the PHY header in the case that there are one or moretypes of information transmitted to the PHY header.

However, the PHY header indicator field may be omitted depending on asituation.

In addition, in the case that the PHY header indicator field is notincluded in the PHY header, it may be defined that the PHY headerincludes the NDI field always.

It is preferable that the NDI field proposed in the present disclosureis transmitted through PHY control information.

Accordingly, the NDI field transmitted as a MAC PDU is forwarded to aPHY layer after being decoded.

In the case that the NDI field is set to a value representing new data,an eNB may discard or separately store a previous data (or coded bit)stored with respect to a HARQ process ID.

According to the first embodiment, a receiver side (e.g., eNB) performsHARQ process after identifying the PHY header included in a MAC PDU.

That is, according to the first embodiment, after identifying that thedata transmitted together with the PHY header through the PHY header isthe retransmission data first, the HARQ combining should be performedwith a previous data failed to transmit.

Accordingly, in the first embodiment, an independent decoding isadditionally performed for data including the PHY header beforeperforming the HARQ combining, and accordingly, decoding overhead isadditionally occurred such that an eNB receives the retransmission datafrom a UE.

Here, it is preferable to assume that urgent data transmitted by a UE issuccessfully received in an eNB with high probability of 99.9999% orhigher.

FIG. 31 is a flowchart illustrating an example of a decoding method of atransport block including a PHY header proposed in the presentdisclosure.

Referring to FIG. 31, an eNB receives a transport block from a UEthrough a retransmission resource region (allocated to the UE) (step,S3110).

The transport block indicates a MAC PDU including the PHY headerdescribed above.

Later, the eNB checks whether an NDI field is included through the PHYheader indicator field included in the PHY header.

In the case that the NDI field is included, the eNB checks whether thetransport block is new data like urgent data (or Low Latency Radio (LLR)data) and the like or a retransmission data with respect to UL data(previous data) previously transmitted through the NDI field (step,S3120).

In the case that the transport block is new data like urgent data andthe like, the eNB performs the procedure through steps S3121 to S3124.

That is, after the eNB decodes the transport block through a TurboDecoder (step, S3121), the eNB performs a CRC check for the transportblock (step, S3122).

Depending on whether the CRC check of step S3122 is succeeded (step,S3123), the eNB performs the following procedures.

In the case that the eNB succeeded to CRC check in step S3123, the eNBtransmits HARQ ACK to the UE, and discard (HARQ buffer flush) orseparately store the code bits stored in the HARQ buffer in relation tothe corresponding HARQ process ID (step, S3124).

In the case that the eNB fails to CRC check in step S3123, the eNBtransmits HARQ NACK to the UE (step, S3170).

As a result of checking in step S3120, in the case that the transportblock is the retransmission data, the eNB performs the existing HARQprocess (procedure through steps S3130 to S3170).

That is, the eNB performs HARQ combining of the initial transport blockand the retransmitted transport block (step, S3130).

Later, after the eNB performs (turbo) decoding for the transport blockcombined in step S3130 through the turbo decoder (step, S3140), the eNBCRC checks for the corresponding transport block or whether a maximumretransmission count is exceeded (steps S3150 and S3160).

In the case that the CRC check is successful, the eNB performs stepS3124. That is, the eNB transmits HARQ ACK to the UE, and flushes theHARQ buffer in relation to the corresponding HARQ process ID.

In the case that CRC check is failed and the maximum retransmissioncount is not exceeded, the eNB performs step S3170. That is, the eNBtransmits HARQ NACK to the UE.

(2) Second Embodiment: A Method for Transmitting NDI Using a New CRCType

Next, a second embodiment in which NDI information is transmitted usinga new Cyclic Redundancy Check (CRC) type will be described.

The second embodiment represents a method for transmitting the NDIinformation indicating whether it is a retransmission data or a new databy using different CRC bits from each other with respect to theretransmission data and newly transmitted data (e.g., urgent data).

Previously, 24-bit CRC is used for performing CRC check.

The 24-bit CRC includes two types (CRC 24A and CRC 24B) as describedabove.

CRC 24A is used for a transport block CRC and CRC 24B is used for a codeblock CRC.

The second embodiment newly defines CRC 24A′ or CRC 24B′ fortransmitting a New Data Indicator (NDI) that represents it is new data.

That is, in order to transmit new data using a retransmission resource,a UE may transmit the new data by attaching CRC defined as CRC 24A′ orCRC 24B′ to a transport block (TB) or a code block (CB) for the new datato an eNB.

In the case that TB segmentation occurs for the data transmitted by a UEand data is generated in a CB unit, the UE should notify NDI informationto an eNB by using CRC 24B′ instead of CRC 24A′.

In the case that TB segmentation does not occur for the data transmittedby a UE (in the case that a TB is transmitted without any change), theUE should notify NDI information using CRC 24A′ for transmitting newdata.

FIG. 32 illustrates a CRC check procedure in the case that TBsegmentation does not occur for the data transmitted by a UE.

Particularly, FIG. 32 shows CRC check process of the case that TBsegmentation does not occur for data transmitted by a UE.

Referring to FIG. 32, an eNB receives UL data from a UE through aretransmission resource allocated to the UE (step, S3210).

Later, the eNB determines whether CRC check is performed with CRC 24A(step, S3220).

In the case that the eNB does not perform CRC check with CRC 24A, theeNB performs HARQ combining of an initial TB stored in HARQ buffer and aretransmission TB (step, S3230).

Later, the eNB performs (turbo) decoding of a Combined Transport Blockthrough a turbo decoder (step, S3240), and then, performs CRC check withCRC 24A (step, S350).

When the CRC check with CRC 24A is succeeded, the eNB identifies thedata received through a retransmission resource is the retransmissiondata (steps, S3260 and S3270).

That is, the eNB identifies that the retransmission data is successfullyreceived from the UE, transmits HARQ ACK to the UE, and flushes thecorresponding HARQ buffer.

However, when the CRC check with CRC 24A is failed, the eNB performs CRCcheck with CRC 24A′ through steps S3221 and S3222 (steps, S3221 andS3222).

The reason why step S3222 is performed is because it is unable to knowwhether the cause of failure of CRC check with CRC24A is due to the newdata or the retransmission data reception error.

That is, the eNB performs (turbo) decoding of a TB transmitted withoutHARQ combining with an initial transport block through a turbo decoder(step, S3221).

Later, the eNB performs CRC check of decoded TB with CRC 24A′ (step,S3222).

Then, when the CRC check in step S3222 is succeeded, the eNB identifiesthat the data transmitted through the TB is new data, and forwards thecorresponding data to a higher layer (steps, S3223 and S3224).

However, when the CRC check in step S3222 is failed, the eNB regards thedata transmitted through the TB as the retransmission data and transmitsHARQ NACK to the UE, and requests to retransmit the corresponding data(steps, S3223 and S3225).

The retransmission request for the corresponding data is performedwithin the range that does not exceed a maximum retransmission count.

As described above, it is preferable that the second embodiment isapplied to the case that new data is transmitted to an eNB from a UEwith high reliability and HARQ is not applied.

In the case that an error occurs for the new data that the UE transmitsto the eNB, owing to HARQ combining of wrong data, the HARQ performancein a receiver side (e.g., eNB) may be decreased.

In addition, it is understood that the second embodiment may beidentically applied to the case that TB segmentation occurs and CRCcheck is performed with a unit of code block (CB).

In this case, the CRC attached to a CB is CRC 24B′ instead of CRC 24B.That is, by attaching CRC 24B′ to a CB, it is notified that thecorresponding CB is a new CB, not a retransmission CB.

In the case of a transmission in a unit of CB, the CRC attached to a TBis CRC 24A′, not CRC 24A.

As such, since a unit of HARQ combining acts as a CB in a transmissionof a unit of CB, CRC 24B′ may be used.

However, when combining and CRC check of CB unit operate in serial for nnumber of CBs, in the case that the CRC check with CRC 24B′ issuccessfully performed for even one of n number of CBs, thecorresponding TB may be determined to be a TB for new data.

In addition, in the second embodiment, it is exemplified that the CRCcheck (CRC 24A or CRC 24B) for the retransmission data is performedfirst, and then the CRC check (CRC 24A′ or CRC 24B′) for new data isperformed, as described in FIG. 32, but it is also available that theCRC check (CRC 24A′ or CRC 24B′) for new data is performed first, andthen the CRC check (CRC 24B) for the retransmission data is performedfor the case that the CRC check for new data is failed, as shown in FIG.33.

FIG. 33 is a flowchart illustrating another example of a method fordecoding a transport block through new CRC check proposed in the presentdisclosure.

FIG. 33 is a diagram illustrating the case that the CRC check for newdata is performed first, and particularly, TB segmentation occurs andthe CRC check is performed in a unit of CB.

That is, an eNB performs (turbo) decoding through a turbo decoder forthe TB received from a UE, and then, performs CRC check of the TB withCRC 24B′ (step, S3310).

In the case that the CRC check with CRC 24B′ is failed, the eNB performsCRC check of the TB with CRC 24B (step, S3320).

Accordingly, in the case that the CRC check of the TB with CRC 24B′ issucceeded, the eNB knows that the corresponding TB is for new data, andin the case that the CRC check of the TB with CRC 24B is succeeded, theeNB knows that the corresponding TB is for the retransmission data.

In the case that a probability of transmitting retransmission data usinga retransmission resource is high in the second embodiment, the methodas described in FIG. 32 may be efficient.

However, in the second embodiment, since a decoding time for new data isadded, in the case of a transmission of data sensitive to datatransmission delay, it may be preferable to use the method described inFIG. 33.

Otherwise, in the case that it is hard to divide retransmission dataafter HARQ combining for initial data and retransmission data isperformed in an eNB, it may also preferable to use the method describedin FIG. 33.

(3) Third Embodiment: A Method for Transmitting NDI Using UL-SCH Data ina PUSCH Resource and Multiplexing of NDI Signaling

Next, a third embodiment that NDI information is transmitted usingmultiplexing of UL-SCH data and NDI signaling (information) in a PUSCHresource will be described.

The third embodiment provides a method for transmitting controlinformation (e.g., NDI information) indicating whether it is new data orretransmission data through a PUSCH resource that a UE is allocated byan eNB by multiplexing it while transmitting UL-SCH data.

LTE(-A) defines that CQI/PMI, HARQ ACK/NACK or RI information istransmitted by being multiplexed with UL-SCH data before DiscreteFourier Transform (DFT)-spreading is performed.

As a similar method to this, the third embodiment provides a method fortransmitting an indicator (NDI information) indicating whether datatransmitted using a retransmission resource is retransmission data ornew data with being multiplexed with UL-SCH data.

As shown in FIG. 34 (FIG. 34a and FIG. 34b ), an eNB may allocate aspecific RE in a PUSCH resource allocated to a UE for the NDIinformation.

The UE does not transmit UL-SCH data with the RE allocated for the NDI.

In addition, the UE may receive the resource region in which the NDI isallocated through higher layer signaling (e.g., RRC/MAC) semi-staticallyor may be dynamically allocated through a UL grant.

FIG. 34 is a diagram illustrating an example of a method for mapping aresource element (RE) for NDI proposed in the present disclosure.

That is, FIG. 34 shows an example of a method for multiplexing NDI andUL-SCH data.

Particularly, FIG. 34a shows an example that each of four REs of NDIinformation is allocated to 0, 6^(th), 7^(th) and 13^(th) symbols 3410of a lowest subcarrier index of a PUSCH resource, respectively.

FIG. 34b shows an example that four REs are allocated to 2^(nd), 4^(th),9^(th) and 11^(th) symbols 3420 of a center subcarrier index of a PUSCHresource, respectively.

As shown in FIG. 34, the RE resource allocated for CQI/PMI, HARQACK/NACK and RI should not be overlapped with the RE resource allocatedfor the NDI.

In the third embodiment, all types of NDI may be allocated for resourceregions that may be multiplexed with UL-SCH data.

In addition, in the third embodiment, the NDI may be transmitted withbeing multiplexed with HARQ ACK/NACK transmitted in the existing PUSCHregion.

Table 10 below is a table defining a method for distinguishing HARQACK/NACK from NDI by using an orthogonal sequence when the NDI istransmitted with being multiplexed with HARQ ACK/NACK.

TABLE 10 Index Sequence Index Orthogonal Sequence HARQ A/N 0 [+1, +1,+1, +1] NDI 1 [+1, −1, +1, −1]

2. UE and eNB Operation

Hereinafter, a method for performing an operation of a UE and an eNBaccording to whether to perform HARQ for urgent data or preemption datawill be described in more detail based on the contents described above.

First, in the case that HARQ is not performed for urgent data orpreemption resource, an operation of a UE and an eNB in relation to ULdata transmission/reception using a retransmission resource will bedescribed.

In the case that HARQ is not performed for urgent data or preemptiondata, a UE transmits urgent data using a retransmission resource andperforms a retransmission for the previous data which is unable to betransmitted owing to an urgent data transmission in an SF after 8 ms.

That is, while an eNB stores data received with respect to thecorresponding HARQ process ID in advance in a HARQ buffer through NDIinformation, the eNB receives retransmission data unable to receiveafter 8 ms from an urgent data transmission time of the UE.

The eNB performs HARQ combining between the data stored in the HARQbuffer and retransmission data received after 8 ms, and transmits HARQresponse (ACK/NACK) to the corresponding UE.

In this case, the eNB transmits HARQ NACK indicating that retransmissiondata reception for the corresponding HARQ process ID is failed to theUE, but does not transmit the HARQ ACK/NACK for a new data reception,and accordingly, the UE may transmit retransmission data to the eNB byusing a retransmission resource after 8 ms from the urgent datatransmission time of the UE.

FIG. 35 is a diagram illustrating an example of a HARQ operation methodin the case that HARQ process is not performed for a UL datatransmission through a preemption resource proposed in the presentdisclosure.

In FIG. 35, assuming that UL data that a UE transmits using a preemptionresource is transmitted with high transmission success probability, theHARQ process for UL data transmitted using the preemption resource maybe omitted.

At this time, the UE may receive HARQ NACK from an eNB for the datatransmitted with the preemption resource.

In this case, the UE identifies that the received HARQ NACK istransmitted as a result of data reception failure for HARQ process ID 0being performed already.

At this time, the UE may be newly allocated with a retransmissionresource through a UL grant transmitted with the HARQ NACK or mayretransmit data for HARQ process ID 0 that is intended to retransmit inthe same position as a UL resource initially allocated in non-adaptivescheme.

Next, when HARQ is performed for urgent data or preemption resource, anoperation of a UE and an eNB in relation to UL datatransmission/reception using a retransmission resource will bedescribed.

In the case that HARQ is performed for urgent data or preemptionresource, as soon as an eNB receives new data transmitted with NDIinformation, the eNB discards data stored in a HARQ buffer and performsHARQ process for the new data.

FIG. 36 is a diagram illustrating an example of a HARQ operation methodin the case that HARQ is performed for new data transmitted using aretransmission resource proposed in the present disclosure.

Referring to FIG. 36, a UE transmits new data to an eNB together withNDI information through the methods described above in N=8 SF (step,S3610).

Later, the eNB discards data previously received stored in a HARQbuffer, and when a reception of the new data is failed, transmits a newUL grant for retransmitting the new data while transmitting PHICH NACKto the UE (steps, S3620 and S3630).

Here, the data corresponding to PID=0 in N=16 SF indicates new data, notdata previously transmitted.

Later, the UE retransmits the new data to the eNB based on the new ULgrant (step, S3640).

FIG. 37 is a diagram illustrating an example of a HARQ operation methodin the case that HARQ is performed for new data transmitted using aretransmission resource proposed in the present disclosure.

Different from FIG. 36, an eNB changes the HARQ process ID in relationto previous data for retransmitting the previous data to other HARQprocess ID, instead of discarding the previous data received from a UE(before an urgent event occurs), and accordingly, the eNB may newlyallocate a resource for retransmitting the previous data and is able toperform a retransmission of the previous data.

Here, in order to change the HARQ process ID to other HARQ process ID,the other HARQ process ID should be empty.

In the case that the other HARQ process ID is not empty, the eNB maystand by (or wait) until the other HARQ process ID becomes empty.

Referring to FIG. 37, the eNB identifies that the eNB fails to receivethe retransmission data transmitted with PID 0 through a reception ofNDI information from a UE.

Accordingly, the eNB identifies whether there is an empty HARQ processID (PID) of the UE first. In the case that there is an empty HARQ PID ofthe UE, the eNB may transmit a new UL grant for notifying that the HARQprocess for PID 0 is switched (or changed) to other HARQ process ID(step, S3710).

That is, in the case that the eNB identifies that the NDI information ofthe UE transmitted in N=8 SF and the data (data transmitted by the UE inN=0 SF) received previously according to urgent data are failed totransmit in N=10 SF, the eNB notifies that PID of the data previouslyreceived is changed to PID=6 to the UE by transmitting a new UL grant tothe UE.

Accordingly, the UE may perform a retransmission of the previous datacorresponding to PID=6 in N=14 SF, and also perform a retransmission ofurgent data corresponding to PID=0 in N=16 SF.

As shown in FIG. 37, the method of notifying that PID is switched from‘0’ to ‘6’ may include (1) a method of defining previous PID field in aUL grant (method 1) and (2) a method of transmitting a UL grant andprevious PID through a MAC PDU (method 2).

First, method 1 is a method of newly defining a previous PID fieldindicating a HARQ process ID in relation to previous data in a UL grant.

In the case that UL HARQ operates as synchronous HARQ, by newly defininga previous PID field in a UL grant, it may be indicated that data whichis transmitting with the previous PID (PID 0) is changed to a PID (PID6) for the resource indicated by the UL grant.

In the case that it is hard to newly define a previous PID field in theUL grant, method 2 below may be used.

Method 2 is a method defining a new MAC PDU or a MAC control element(CE) for transmitting the previous PID value.

That is, according to method 2, a new MAC PDU or a MAC CE including theprevious PID is transmitted together with a UL grant transmission, andaccordingly a UE may continue to perform a transmission for the previousdata.

In summary, in the case that an urgent event occurs on a UE and the UEis required to transmit an urgent data, the present disclosure providesa method for transmitting the urgent data using a resource allocated tothe UE itself.

Previously, a UE was able to transmit data more quickly by occupying aresource of which priority is high according to uplink dataprioritization in the UE by using the resource allocated to the UEitself.

However, in the case that a UE transmit a different data from an initialtransmission using a HARQ retransmission resource, as described above, aproblem that a HARQ process does not operate properly may occur.

The retransmission resource of the UE is also a resource that an eNBallocates to the UE in order to transmit a data, but even in the casethat data of which priority is high is generated in the UE, the UE maytransmit the abruptly generated data with being allocated with a newresource only after waiting for retransmission of all of the previousdata being completed, owing to the reason described above.

As such, in the case that a HARQ retransmission is performing on thetime when the urgent data is generated, long time delay may occur for auser equipment to perform a resource request for an urgent datatransmission.

In the worst case, in the case that HARQ retransmission is generated asmuch as the maximum retransmission count and all (8 for LTE) HARQprocesses are performing, a UE is able to be newly allocated with aresource for the urgent data after maximum 32 ms.

However, by using the method proposed in the present disclosure, thedata transmission in which delay time may require maximum 32 ms may beperformed within 1 to 3 ms, and there is an effect of transmittingurgent data more quickly and safely.

General Apparatus to which the Present Invention May be Applied

FIG. 38 illustrates a block diagram of a wireless communicationapparatus to which the methods proposed in the present disclosure may beapplied.

Referring to FIG. 38, the wireless communication system includes a basestation (eNB) 3810 and a plurality of user equipments (UEs) 3820 locatedwithin the region of the eNB 3810.

The eNB 3810 includes a processor 3811, a memory 3812 and a radiofrequency unit 3813. The processor 3811 implements the functions,processes and/or methods proposed in FIGS. 1 to 37 above. The layers ofwireless interface protocol may be implemented by the processor 3811.The memory 3812 is connected to the processor 3811, and stores varioustypes of information for driving the processor 3811. The RF unit 3813 isconnected to the processor 3811, and transmits and/or receives radiosignals.

The UE 3820 includes a processor 3821, a memory 3822 and an RF unit3823. The processor 3821 implements the functions, processes and/ormethods proposed in FIGS. 1 to 37 above. The layers of wirelessinterface protocol may be implemented by the processor 3821. The memory3822 is connected to the processor 3821, and stores various types ofinformation for driving the processor 3821. The RF unit 3823 isconnected to the processor 3821, and transmits and/or receives radiosignals.

The memories 3812 and 3822 may be located interior or exterior of theprocessors 3811 and 3821, and may be connected to the processors 3811and 3821 with well known means.

In addition, the eNB 3810 and/or the UE 3820 may have a single antennaor multiple antennas.

The embodiments described so far are those of the elements and technicalfeatures being coupled in a predetermined form. So far as there is notany apparent mention, each of the elements and technical features shouldbe considered to be selective. Each of the elements and technicalfeatures may be embodied without being coupled with other elements ortechnical features. In addition, it is also possible to construct theembodiments of the present invention by coupling a part of the elementsand/or technical features. The order of operations described in theembodiments of the present invention may be changed. A part of elementsor technical features in an embodiment may be included in anotherembodiment, or may be replaced by the elements and technical featuresthat correspond to other embodiment. It is apparent to constructembodiment by combining claims that do not have explicit referencerelation in the following claims, or to include the claims in a newclaim set by an amendment after application.

The embodiments of the present invention may be implemented by variousmeans, for example, hardware, firmware, software and the combinationthereof. In the case of the hardware, an embodiment of the presentinvention may be implemented by one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), a processor, a controller, amicro controller, a micro processor, and the like.

In the case of the implementation by the firmware or the software, anembodiment of the present invention may be implemented in a form such asa module, a procedure, a function, and so on that performs the functionsor operations described so far. Software codes may be stored in thememory, and driven by the processor. The memory may be located interioror exterior to the processor, and may exchange data with the processorwith various known means.

It will be understood to those skilled in the art that variousmodifications and variations can be made without departing from theessential features of the inventions. Therefore, the detaileddescription is not limited to the embodiments described above, butshould be considered as examples. The scope of the present inventionshould be determined by reasonable interpretation of the attachedclaims, and all modification within the scope of equivalence should beincluded in the scope of the present invention.

INDUSTRIAL APPLICABILITY

The method for transmitting uplink data in a wireless communicationsystem of the present invention has been described mainly with theexample applied to 3GPP LTE/LTE-A system, but may also be applied tovarious wireless communication systems except the 3GPP LTE/LTE-A system.

The invention claimed is:
 1. A method for transmitting, by a userequipment (UE), an uplink (UL) data in a wireless communication system,the method comprising: receiving a first UL grant from a base station(BS); transmitting, to the BS, a first UL data based on the first ULgrant; receiving a hybrid automatic repeat request (HARQ) response ofthe first UL data from the BS; and transmitting, to the BS, a second ULdata and control information for whether the second UL data is aretransmission data of the first UL data or a new data, wherein thesecond UL data and the control information are multiplexed on a physicaluplink shared channel (PUSCH) resource, wherein the control informationrelates to a type of a cyclic redundancy check (CRC), wherein, when thesecond UL data is the retransmission data of the first UL data, thecontrol information relates to a first CRC type, and wherein, when thesecond UL data is the new data, the control information relates to asecond CRC type.
 2. The method of claim 1, when the second UL data isthe retransmission data of the first UL data the method furthercomprises: receiving a second UL grant from the BS; and transmitting, tothe BS, the second UL data based on the received second UL grant,wherein the second UL grant is received from the BS together with theHARQ response.
 3. The method of claim 1, wherein the type of CRC isdetermined depending on whether a transport block (TB) of theretransmission data or the new data is segmented.
 4. The method of claim1, wherein the control information is mapped to a specific resourceelement (RE) of the PUSCH resource, and wherein a resource of the secondUL data and a resource of the control information are not overlapped. 5.The method of claim 4, wherein the control information is mapped to atleast one symbol of a lowest subcarrier index of the PUSCH resource ormapped to at least one symbol of a center subcarrier index of the PUSCHresource.
 6. The method of claim 1, further comprising: receiving adownlink (DL) data from the BS; and transmitting a HARQ response of thereceived DL data to the BS, wherein the control information istransmitted with being multiplexed with the HARQ response of thereceived DL data.
 7. The method of claim 6, wherein the controlinformation and the HARQ response of the received DL data aredistinguished by an orthogonal sequence.
 8. The method of claim 1,wherein the control information is a new data indicator (NDI).
 9. Amethod for receiving, by a base station (BS), an uplink (UL) data in awireless communication system, the method comprising: transmitting afirst UL grant to a user equipment (UE); receiving a first UL data fromthe UE; transmitting, to the UE, a hybrid automatic repeat request(HARQ) response of the first UL data; and receiving, from the UE, asecond UL data and control information for whether the second UL data isa retransmission data of the first UL data or a new data, wherein thesecond UL data and the control information are multiplexed on a physicaluplink shared channel (PUSCH) resource, wherein the control informationrelates to a type of a cyclic redundancy check (CRC), wherein, when thesecond UL data is the retransmission data of the first UL data, thecontrol information relates to a first CRC type, and wherein, when thesecond UL data is the new data, the control information relates to asecond CRC type.
 10. The method of claim 9, further comprising:determining to perform HARQ combining between the first UL data and thesecond UL data based on the received control information.
 11. The methodof claim 10, wherein when the second UL data indicates theretransmission data of the first UL data, the first UL data and thesecond UL data are HARQ combined, and wherein when the second UL dataindicates the new data, the first UL data stored in a HARQ buffer isdiscarded or separately stored.
 12. The method of claim 11, wherein whenthe second UL data is the new data, the method further comprises:transmitting, to the UE, a HARQ NACK for a reception failure of thefirst UL data; and receiving, from the UE, the retransmission data ofthe first UL data.
 13. The method of claim 12, further comprising:transmitting, to the UE, a second UL grant for newly allocating aretransmission resource of the first UL data; and receiving, from theUE, the retransmission data of the first UL data based on the second ULgrant.
 14. The method of claim 12, further comprising: transmitting, tothe UE, indication information indicating that a HARQ process identifier(ID) of the first UL data is changed.
 15. The method of claim 11,wherein when the second UL data is the new data, the method furthercomprises: transmitting, to the UE, a HARQ NACK for a reception failureof the first UL data; and receiving, from the UE, the retransmissiondata of the second UL data.
 16. A user equipment (UE) for transmittingan uplink (UL) data in a wireless communication system, the UEcomprising: a radio frequency (RF) module including a transceiver fortransmitting and receiving a radio signal; and a processor functionallyconnected to the RF module, wherein the processor is configured to:receive a first UL grant from a base station (BS); transmit, to the BS,a first UL data based on the first UL grant; receive a hybrid automaticrepeat request (HARQ) response of the first UL data from the BS; andtransmit, to the BS, a second UL data and control information forwhether the second UL data is a retransmission data of the first UL dataor a new data, wherein the second UL data and the control informationare multiplexed on a physical uplink shared channel (PUSCH) resource,wherein the control information relates to a type of a cyclic redundancycheck (CRC), wherein, when the second UL data is the retransmission dataof the first UL data, the control information relates to a first CRCtype, and wherein, when the second UL data is the new data, the controlinformation relates to a second CRC type.